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Guarantor Mortgage NZ — Using Family Equity to Buy a Home

Updated

A guarantor mortgage allows a family member — usually parents — to use equity in their own property to help you buy a home. It’s one of the most effective ways to overcome the deposit barrier, but it comes with real financial risk for the guarantor. Understanding exactly how it works is essential before approaching family.

What Is a Guarantor Mortgage?

In a guarantor mortgage, a third party (typically parents or close family) provides additional security for your home loan by allowing the lender to place a mortgage over their property. This additional security supplements yours.

Without a guarantor:

  • Property value: $700,000
  • Your deposit: $60,000 (8.6%)
  • Loan: $640,000
  • LVR: 91.4% — most banks won’t lend at this LVR

With a guarantor:

  • Property value: $700,000
  • Your deposit: $60,000
  • Guarantor’s equity pledged: $80,000 (from their property)
  • Effective security: $700,000 + $80,000 = $780,000
  • Loan: $640,000
  • Effective LVR: 82% — brings it within a lending range banks may accept

The guarantor doesn’t give you money — they give you access to their property equity as security.

How the Guarantee Is Structured

Guarantees are typically structured as a limited guarantee (a specific amount of the guarantor’s property as security) rather than a full guarantee over the entire loan.

Limited guarantee example:

  • Your loan: $640,000
  • Bank requires 80% LVR maximum
  • Required security: $640,000 / 80% = $800,000
  • Your property provides: $700,000
  • Shortfall: $100,000 → the guarantee amount is $100,000

The bank places a mortgage over the guarantor’s property for $100,000. As you pay down your loan and/or your property increases in value, the guarantee amount can be reduced and eventually removed.

Guarantee removal: The guarantee can be removed (the mortgage lifted from the guarantor’s property) when your LVR falls to 80% or below — typically when:

  • You’ve paid down enough principal, or
  • Your property has increased in value sufficiently

This typically takes 3–7 years depending on property growth and repayments.

Eligibility Requirements

For the guarantor:

  • Must own property with sufficient equity (the guarantee amount must be available as unencumbered equity)
  • Must have a mortgage capacity assessment — the bank will check the guarantor’s own financial position
  • Must be a New Zealand resident (most lenders require this)
  • Must receive independent legal advice before signing (required by NZ law)

For the borrower:

  • Must demonstrate ability to service the loan from their own income (the guarantee helps with security/LVR — it doesn’t substitute for income)
  • Must meet the bank’s standard lending criteria (income, credit, employment)

The Risks for the Guarantor — Be Honest About These

This is a genuine financial risk, not a symbolic gesture. If the borrower can’t repay the mortgage and defaults, the bank can:

  1. Seek repayment from the borrower (sell the property)
  2. If the proceeds don’t cover the loan, exercise the guarantee and sell the guarantor’s property to recover the shortfall (up to the guarantee amount)

In a worst case scenario:

  • Borrower loses job and can’t service the loan
  • Property has fallen in value (e.g., post-COVID-style downturn)
  • Bank sells property but doesn’t recover the full loan amount
  • Bank recovers the $100,000 shortfall from the guarantor’s property

The guarantor loses $100,000 of equity in their home. This is real and has happened in NZ.

Every guarantor must:

  1. Receive independent legal advice before signing — this is a legal requirement in NZ
  2. Understand they could lose the guaranteed amount
  3. Be financially able to absorb a worst-case loss
  4. Understand the release conditions and estimated timeline

The Conversation with Family

Guarantor mortgages are emotionally complex. Before approaching family:

Be transparent:

  • Share your full financial position — income, debts, expenses
  • Be honest about the risks if things go wrong
  • Don’t downplay the financial commitment you’re asking them to make

Discuss exit conditions:

  • When and how the guarantee will be removed
  • What happens if you need to sell the property during the guarantee period
  • What happens if the guarantor needs access to their equity (e.g., their own refinancing)

Make it formal:

  • Both parties should receive independent legal advice
  • Document the understanding (your solicitor can help with this)
  • Agree upfront on how you’ll communicate if financial difficulties emerge

Consider the relationship:

  • Financial stress can damage family relationships
  • If things go wrong, the bank’s claim is against the guarantor’s property — not a moral discussion
  • Make sure both parties enter this with clear eyes about the risk

Alternatives to a Guarantor

If a guarantor arrangement isn’t right for your family situation:

AlternativeHow it works
Gifted depositFamily gives you cash for your deposit outright (no security over their property)
First Home LoanKāinga Ora 5% deposit, no guarantee required if income-eligible
SavingsBuild to 20% deposit over time
KiwiSaver + First Home LoanCombine KiwiSaver withdrawal with 5% top-up
New build purchase10% deposit, LVR-exempt

See Low Deposit Mortgage NZ for a comparison of all options.

Further Reading