Every New Zealand mortgage repayment falls into one of two structures: a standard table loan, where each payment reduces both interest and principal, or interest-only, where the loan balance doesn't move at all until the interest-only period ends. Banks here have tightened who qualifies for the second option considerably in recent years — it's still available, but it's no longer a default choice the way it once was.
The Two Structures
Table loan (principal & interest): the standard NZ mortgage structure. Each payment is a fixed amount, split between interest and principal, following the familiar amortization curve — interest-heavy early on, shifting toward principal over the term.
Interest-only: payments cover interest alone, typically for a defined period (commonly 1-5 years) rather than the whole loan term. The balance stays exactly where it started until the interest-only period ends, at which point payments step up to a table-loan structure recalculated against the remaining term.
Worked Example
On the $520,000 loan at 5.99% from our Mortgage Calculator example, over a 30-year table loan:
| Structure | Monthly Payment | Balance After 5 Years |
|---|---|---|
| Table loan (P&I) | ≈ $3,114 | ≈ $493,000 |
| Interest-only (5-yr period) | ≈ $2,596 | $520,000 (unchanged) |
The interest-only payment is lower month to month, but at the 5-year mark, the table loan borrower has paid down roughly $27,000 of principal, while the interest-only borrower still owes the full original amount — and their payment steps up sharply once the interest-only period ends and the remaining balance is re-amortized over a shorter remaining term.
Common Mistakes
Borrowers frequently choose interest-only purely to lower their monthly payment without a specific plan for what happens when the period ends — banks increasingly require evidence of a credible strategy (a lump sum, planned sale, or investment vehicle) before approving it, particularly for owner-occupied lending.
Borrowers also assume interest-only is mainly for investment properties — while it is more common there (since it can maximise the tax-deductible interest component relative to rental income), it remains available for owner-occupied lending too, just under tighter conditions than in the past.
A third mistake: not budgeting for the payment step-up at the end of the interest-only period — treating the lower initial payment as the permanent number, rather than a temporary phase with a known, calculable increase coming.
Where This Calculator Has Limits
It shows the two structures at their simplest — some borrowers use a part table-loan, part interest-only split, which this direct comparison doesn't model. It also can't confirm whether a specific lender will approve an interest-only application without knowing your full financial picture and their current lending policy.
Frequently Asked Questions
Is interest-only still available for owner-occupied homes in New Zealand?
Yes, though banks apply tighter criteria than in the past, generally requiring a credible plan for repaying the principal once the interest-only period ends.
Does interest-only cost more overall?
Yes — since the balance doesn't reduce during the interest-only period, more total interest accrues over the life of the loan compared to an equivalent table loan.
What happens automatically when my interest-only period ends?
Payments switch to a table-loan structure, recalculated to fully repay the remaining balance over whatever term is left — this step-up is worth planning for well in advance.
Is interest-only more common for investment properties?
Yes, considerably — many investors use it to maximise the interest-deductible portion of their loan while relying on rental income and property appreciation as the underlying strategy.
Can I extend my interest-only period when it ends?
Sometimes, subject to your bank's current lending policy and your financial circumstances at the time — it's not automatic and generally requires a fresh application or review.
Related Tools
Mortgage Calculator · Rental Yield Calculator · LVR Calculator
Educational content, not financial advice. Interest-only eligibility and lending criteria vary by bank and change over time — confirm your specific options with a licensed New Zealand mortgage adviser. Written by the MortgagePro Global team.