How Home Loans Work in NZ — A Plain-English Guide | MoneyBalance

A mortgage might be the largest contract you ever sign — yet the mechanics behind it are rarely explained clearly. Most people know they’ll pay interest, but few understand how repayments are structured, why so much interest is paid in the early years, or how changing from a 25-year to a 30-year term affects the total cost.

This guide explains how NZ home loans actually work, from first drawdown to final repayment.

The Basic Structure: What You’re Actually Agreeing To

When a bank approves your mortgage, you are agreeing to:

Repay the principal — the amount you borrowed
Pay interest on the outstanding balance, calculated at the agreed rate
Secure the loan against the property (the bank has a registered mortgage over the title)

If you fail to make repayments and cannot resolve the situation with the lender, the bank can appoint a mortgagee and sell the property to recover what is owed. This is called mortgagee sale, and is the legal foundation that allows banks to offer large loans at relatively low rates.

How Repayments Are Calculated: Table Loans

The vast majority of New Zealand home loans are table loans (also called principal-and-interest loans). The defining feature is that every repayment is the same dollar amount — but the split between interest and principal changes over time.

How it works

Interest is calculated on the outstanding loan balance
As you repay principal, the balance falls — so the interest component of each repayment falls too
Because the total repayment is fixed, the principal component increases as interest falls
Over time, more and more of each repayment chips away at the debt

This structure is called amortisation.

Example: $700,000 loan at 6.00% over 30 years

Year	Annual interest paid	Annual principal paid	Remaining balance
1	$41,570	$8,762	$691,238
5	$39,500	$10,832	$657,424
10	$36,530	$13,802	$609,720
15	$32,310	$18,022	$543,988
20	$26,300	$24,032	$453,104
25	$17,610	$32,722	$325,692
30	$5,200	$45,132	$0

Monthly repayment: ~$4,199. Total interest paid over 30 years: ~$811,640.

The first few years are dominated by interest. This is why making extra repayments early in a mortgage has a disproportionate impact — every extra dollar paid reduces the principal on which future interest is calculated.

Interest Rate Types: Fixed, Floating, and Revolving

Fixed rate

The interest rate is locked in for a set term — typically 6 months, 1, 2, 3, or 5 years. Repayments don’t change during the fixed period.

What happens at the end of a fixed term? When the fixed term expires, the loan “rolls over.” If you don’t act, the bank will automatically move you to its standard floating rate or a default fixed term — which is rarely competitive. This rollover moment is your chance to negotiate a better rate, change your term, or refinance.

Break fees: If you need to exit a fixed rate mortgage before the term ends (because you’re selling, refinancing, or making a large lump-sum repayment), the bank may charge a break fee. This compensates the bank for the loss of the fixed-rate income stream. Break fees can range from nothing to tens of thousands of dollars depending on how rates have moved and how much time remains.

Floating (variable) rate

The interest rate moves up or down with market conditions — mainly driven by the RBNZ’s Official Cash Rate (OCR). Floating rates are usually higher than short-term fixed rates, but they offer:

No break fees for lump-sum repayments
Flexibility to switch to fixed at any time
Repayments that drop automatically when the OCR falls

Revolving credit

A revolving credit mortgage works like a large overdraft. Instead of a fixed repayment schedule, you deposit your salary into the facility and withdraw money as needed. Interest is calculated daily on the outstanding balance, so every day your salary sits in the account, it reduces the amount of interest you’re paying.

Used correctly, a revolving credit facility can cut years off a mortgage without increasing repayments. Used carelessly, it can result in the principal never reducing at all — a real risk for people who treat it like a spending account.

Interest-only loans

An interest-only loan requires only interest payments — the principal doesn’t reduce. These are most common for property investors who want to maximise cash flow and tax deductions. Interest-only terms are typically limited to 5 years for owner-occupiers and require strong justification.

Note: interest deductibility for investors was being phased back in during 2024–2025. Check the current IRD rules before structuring a loan interest-only for investment purposes.

For a detailed comparison of your main options, see our guide on fixed vs floating mortgages in NZ.

Loan Term: 25 Years vs 30 Years

The term of your mortgage determines how long you have to repay it and, significantly, how large your regular repayments are.

Term	Monthly repayment ($700k at 6%)	Total interest paid
20 years	$5,014	$503,360
25 years	$4,494	$648,200
30 years	$4,199	$811,640

A longer term means lower repayments — but dramatically more interest over the life of the loan. Going from 25 to 30 years on a $700,000 loan costs an extra $163,440 in interest.

The practical approach: Many NZ borrowers take a 30-year loan term (for lower required repayments) but pay as though it’s a 25-year loan. This maintains flexibility — if money is tight one month, you only have to make the minimum repayment — while still reducing the term and interest cost substantially when extra repayments are made consistently.

LVR: The Loan-to-Value Ratio

Your loan-to-value ratio (LVR) is the loan amount as a percentage of the property’s value.

Formula: LVR = (Loan Amount ÷ Property Value) × 100

Example: $560,000 loan on a $700,000 property = 80% LVR

The RBNZ sets LVR restrictions that limit how much of a bank’s new lending can exceed certain thresholds:

Buyer type	Maximum LVR	Minimum deposit
Owner-occupier	80%	20%
First home buyer (First Home Loan)	95%	5%
Investor	65%	35%

These aren’t hard bans — banks can approve some lending above these thresholds, but there are caps. In practice, most borrowers need the minimum deposit stated above. For a detailed breakdown, see our LVR restrictions guide.

How Mortgage Drawdown Works

Drawdown is the moment the bank releases the mortgage funds. For a standard residential purchase:

You exchange contracts with the vendor and your solicitor confirms the details
On settlement day, your solicitor requests the funds from the bank
The bank releases the mortgage funds to the vendor’s solicitor
Ownership transfers to you via the Land Information New Zealand (LINZ) register
Your mortgage repayments begin (usually from the following month)

For new builds, drawdown often happens in stages aligned with construction milestones — a “progress payment” structure. Each stage draws down a portion of the approved loan.

What Happens When Interest Rates Change?

If you’re on a fixed rate

Nothing happens during the fixed term. Your repayments stay exactly the same regardless of OCR movements. When the term expires, the rate will be set at whatever the market rate is at rollover.

If you’re on a floating rate

Your repayments adjust (usually within a few weeks) when the bank changes its floating rate — typically in response to an OCR decision. A 0.25% OCR cut on a $500,000 floating loan reduces annual interest by approximately $1,250 — or about $104/month.

Rate risk in practice

New Zealand mortgage borrowers faced a sharp lesson in rate risk in 2022–2023, when the OCR rose from 0.25% to 5.50% in 18 months. Many borrowers who had fixed at historic lows rolled off their terms onto rates two to three times higher, significantly increasing repayments.

This is why loan structure and staggering fixed terms matters: if you have a $700,000 loan, splitting it into a $350,000 1-year fix and a $350,000 2-year fix means you’re never fully exposed to a rate change at once.

Principal Repayment vs Interest-Only: What’s the Difference?

Feature	Principal and interest	Interest-only
Repayment amount	Higher	Lower
Debt reduction	Yes — every repayment reduces the principal	No — principal stays flat
Total cost	Lower over the life of the loan	Higher — you’re never reducing the balance
Common use	Owner-occupiers, long-term wealth building	Property investors, short-term cash flow
Maximum term	Typically 25–30 years	Usually 5 years, then must convert

Most New Zealand owner-occupiers should be on principal-and-interest loans. Interest-only is a tool for specific situations, not a long-term mortgage strategy for owner-occupiers.

Redraw and Extra Repayments

Many NZ mortgages allow extra repayments, and some allow you to redraw those extra payments if needed.

Floating and revolving credit facilities almost always permit extra repayments without restriction
Fixed rate loans typically allow limited extra repayments without break fees — often up to 5% of the original loan amount per year
Redraw allows you to withdraw extra repayments you’ve made if circumstances change — though some fixed-rate products don’t permit this

Making extra repayments is one of the most effective ways to cut the cost of your mortgage. Even $200/month extra on a $600,000 loan at 6% over 25 years saves approximately $57,000 in interest and reduces the term by 3.5 years.

Mortgage Insurance and LMI

New Zealand does not have a compulsory Lenders Mortgage Insurance (LMI) system equivalent to Australia. However:

Some non-bank lenders may charge a low-equity premium or fee for high-LVR lending
The Kāinga Ora First Home Loan scheme involves a government guarantee to the bank, enabling the lender to approve low-deposit applications — borrowers don’t pay a separate LMI premium

For first home buyers using the First Home Loan, this government underwriting removes the main cost barrier associated with high-LVR lending in other markets. For more detail, see our First Home Loan guide.

How Multiple Loans on One Property Work

Many New Zealand borrowers have more than one “split” on their home loan — for example:

Loan 1: $400,000 fixed for 2 years at 5.79%
Loan 2: $200,000 fixed for 1 year at 5.59%
Loan 3: $100,000 floating (for extra repayments/redraw flexibility)

All three splits are secured against the same property. This structure allows borrowers to:

Stagger rollover dates (not all fixed terms expire at once)
Make extra repayments into the floating portion without break fees
Benefit from different rate terms on different portions

Cross-collateralisation is a related (but riskier) structure where the same loan is secured against multiple properties. This is common for property investors but can create problems when selling one property — the bank holds security over everything.

Frequently Asked Questions

What is amortisation? Amortisation is the process of paying off a loan over time through regular repayments. In a fully amortising mortgage, the loan balance reduces to zero by the end of the term. Each repayment covers both interest and principal, with the proportion shifting over time.

Is the interest on a home loan tax deductible in NZ? For owner-occupiers: no. Interest on your primary residence is not tax deductible in New Zealand. For residential rental property investors: interest deductibility was phased out and then progressively restored. As of the 2025–26 tax year, investors can deduct 100% of mortgage interest. Confirm current rules with your accountant or IRD guidance.

What happens if I miss a mortgage repayment? Your bank will contact you. Most lenders have hardship policies — if you proactively communicate, they will often grant a repayment holiday or restructure the loan. If you ignore the issue, penalties accumulate and enforcement action (including mortgagee sale) can follow, though this is a last resort.

Can I increase my mortgage? Yes. This is called a “top-up” or refinance. You’ll need to re-qualify with the bank (income, credit, updated valuation), and sufficient equity in the property is required. Common reasons include home renovations, purchasing an investment property, or debt consolidation.

What is a split loan? A split loan divides your mortgage into multiple portions — each with its own rate type and term. For example, part fixed and part floating. This is the most common NZ mortgage structure and balances rate certainty with flexibility.

How does the bank value my property? Banks commission an independent registered valuation or use an automated valuation model (AVM). If the bank’s valuation comes in below the purchase price, the LVR calculation is based on the lower value — which may increase your required deposit. Getting your own valuation before making an offer can avoid surprises.