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When to Refinance Your Mortgage NZ — Timing and Decision Framework

Updated

Refinancing your mortgage — switching to a new lender for a better rate or structure — can save significant money. But it isn’t always the right move. The timing, break fee cost, and switching costs all affect whether refinancing makes financial sense. This guide gives you a clear framework for the decision.

What Counts as Refinancing?

There are two types of “refinancing” commonly confused:

Refixing with your current lender: Choosing a new fixed term when your current term expires. There’s no switching cost and no new application. This is worth doing at every rollover — compare rates and negotiate before defaulting to whatever rate the bank offers.

Refinancing to a new lender: Moving your mortgage to a different bank entirely. This involves a new application, property valuation, legal transfer, and potentially a break fee if done mid-term. This guide primarily covers this decision.

The Best Time to Refinance: At Rollover

The lowest-friction time to refinance is when your fixed term is about to expire — within 30–60 days of rollover. At this point:

  • Break fee is zero or near-zero (very little remaining fixed term)
  • You already have to do something — refix or let it float
  • All lenders are competing for your business — this is maximum leverage

Most NZ borrowers don’t realise that switching lenders at rollover costs very little extra (mainly legal fees of $500–$1,500) and can access a meaningfully better rate or cashback offer.

Action: 30–60 days before your fixed term expires, research competing bank rates and contact your broker or call other banks. Then go back to your existing bank with the best competing offer and ask them to match it.

Refinancing Mid-Term: When It Makes Sense

Switching mid-term involves paying a break fee — which can be substantial if rates have fallen since you fixed. The decision reduces to a simple calculation:

Is the total interest saving over the remaining term greater than the break fee + switching costs?

The break-even calculation

  1. Get a break fee quote from your current bank
  2. Estimate annual interest saving: (your current rate − new rate) × outstanding balance
  3. Calculate months to break even: break fee ÷ annual saving × 12
  4. If you’ll hold the mortgage longer than the break-even period, refinancing is financially beneficial

Example:

  • Break fee: $12,000
  • New rate: 5.20%, current rate: 6.50%
  • Balance: $650,000
  • Annual saving: $650,000 × 1.30% = $8,450
  • Break-even: 12,000 / 8,450 × 12 = 17 months

If you’re staying in the property for at least 17 months and plan to stay on the new rate, refinancing is profitable. Every month beyond 17 is pure saving.

Switching costs to include:

  • Break fee (from current bank)
  • Legal/conveyancing: $500–$1,500
  • Valuation (new bank may require): $600–$900
  • Discharge fee (current bank): $150–$300

Some banks offer cashback ($1,000–$5,000) to new refinancers — this can offset switching costs significantly or improve the break-even.

Reasons Refinancing Makes Sense

1. Materially lower rate available

If competing banks offer a rate 0.25% or more below what you could renegotiate at your current bank, and the break-even period is within your horizon, refinancing is worth considering.

2. Cashback offer from new lender

Banks regularly offer cashback to attract refinancing customers — typically $2,000–$5,000. This can cover switching costs and accelerate the break-even. Always check the cashback clawback period (if you refinance again within the clawback period, you repay the cashback).

See Cashback Mortgages NZ for how to evaluate cashback offers.

3. Better structure (revolving credit, offset, different split)

Some borrowers refinance not primarily for rate but for product structure — e.g., to access a revolving credit facility their current bank doesn’t offer, or to restructure how their mortgage is split across terms.

4. Current bank won’t negotiate

If your current bank refuses to offer a competitive rate at rollover, switching is how you demonstrate you’re willing to follow through.

5. Equity release for renovation or investment

If your property has gained value since purchase, refinancing can unlock the increased equity. This requires a new valuation and the bank confirming the property supports the higher loan balance.

Reasons Not to Refinance

Large break fee that doesn’t break even

If the break fee is large relative to the potential saving — particularly if you’re planning to sell or pay off the mortgage within a few years — the economics don’t work.

You’re selling soon

If you’re selling the property within 12 months, refinancing to a new lender makes little sense. You’ll pay switching costs and likely trigger a break fee on the new loan when you sell. Better to just let the current loan run or renegotiate the rate at rollover.

Cashback clawback risk

If you took a cashback from your current bank and the clawback period hasn’t expired, you’ll owe the cashback back if you switch. Factor this into the calculation.

Your financial situation has changed

If your income has dropped, LVR has increased (property value fell), or you’ve taken on new debt since your original mortgage, a new application may not get the same terms — or may be declined.

Step-by-Step: How to Refinance in NZ

  1. Check your current fixed term expiry date — note when your term ends
  2. Get a break fee quote from your current bank (in writing)
  3. Research current rates across ANZ, ASB, BNZ, Westpac, Kiwibank — or use a mortgage broker
  4. Run the break-even calculation — determine if refinancing is worth it
  5. Apply with the new lender (or use a broker to apply to multiple simultaneously)
  6. Get a property valuation (if required by the new lender)
  7. Instruct a solicitor to handle the title transfer and discharge of the existing mortgage
  8. Settle — funds from the new lender pay out the old mortgage

Further Reading