Interest Deductibility, CGT, and the 2026 Landlord Vote

The short version: National, ACT, NZ First, Labour and the Green Party are all consistently polling well above the 5% threshold needed to enter Parliament, and the NZ Herald-Motu Research Poll of Polls put the probability of the current National-ACT-NZ First coalition being re-elected at 48.2% as of 25 August 2026. The sixth party in this comparison, Opportunity (formerly branded TOP, still widely searched under that name), is genuinely contested rather than a certainty: the same Poll of Polls model put its probability of clearing 5% at almost 50% as of 15 July 2026. Of the three parties with a confirmed shot at forming the next government, National, ACT and NZ First currently support no change to landlord taxation from where things stand today. Labour has confirmed a 28% capital gains tax on investment property sale profit from 1 July 2027, with the family home excluded, but has not yet said whether it will touch mortgage interest deductibility. The Green Party has confirmed the largest package: removing interest deductibility entirely, a new 45% top tax rate from $160,000, an extended 10-year bright-line test, and a wealth tax that in practice exempts almost every ordinary landlord. Opportunity would keep interest deductibility but introduce an ongoing 1.75% annual tax on urban land value in place of both the bright-line test and any capital gains tax.

I've spent the last few years building RentManager for landlords who run one to four properties themselves, without a property manager or an accountant on retainer, and every election cycle the same question comes up in the emails I get: "what does this actually mean for me?" Most coverage of election tax policy talks in aggregate revenue figures or ideological framing, not what it does to one person's mortgage-and-rent spreadsheet. So this year I pulled together every party's actual stated policy, with sources, and built a calculator so you can run your own numbers rather than trust an example that isn't your situation.

What Is Each Party's Current Policy on Landlord Taxation?

As of 30 August 2026:

• National - no policy change identified. Mortgage interest on rental properties is 100% tax-deductible, the bright-line test is 2 years, there is no capital gains tax, wealth tax, or land tax, and the top personal tax rate stays at 39% above $180,000.
• ACT - supports the current settings above. ACT has separately said it wants to eventually cut the top tax rate from 39% to 33%, but this is a stated ambition rather than a confirmed 2026 coalition commitment, so it isn't the same as a manifesto pledge.
• NZ First - no dedicated 2026 tax manifesto was found for this article. Their position is inferred from their current coalition record: the same settings as National and ACT above.
• Labour - has confirmed a flat 28% tax on investment property sale profit, effective from 1 July 2027, with gains measured from a valuation day rather than retrospectively, and the family home, farms, shares, KiwiSaver and businesses excluded. Leader Chris Hipkins has said fully removing interest deductibility again is "unlikely," but has left the door open to a partial change, such as limiting it to 50%, and has not ruled it out - treat this as an open question, not a settled "no change."
• Green - has confirmed the removal of 100% mortgage interest deductibility, a new top tax bracket of 45% from $160,000, an extension of the bright-line test from 2 to 10 years, and an annual 2.5% wealth tax on individual net worth above $10 million ($20 million as a couple), with the family home exempt.
• Opportunity (formerly branded TOP) - would keep interest deductibility, but replace both the bright-line test and any capital gains tax with an ongoing 1.75% per year tax on the land value of urban rental property (0.5% rural), alongside a $19,400 per year tax-free Citizen's Income paid to every adult. Worth noting: both National and Labour have explicitly ruled out working with Opportunity on this policy in coalition, even if the party clears the 5% threshold, so this scenario has a real chance of never becoming law regardless of the election result.

Every one of these positions can change before polling day, and none of it predicts who wins or what a coalition negotiates afterward - see the note at the top of the calculator below.

How Much Does Removing Interest Deductibility Actually Cost a Landlord?

This is the single biggest lever in the whole comparison, and it works differently to how most people expect. Removing interest deductibility doesn't change what a landlord actually pays their bank each year - the mortgage interest is still a real cash cost either way. What changes is whether that cost reduces taxable rental profit.

Take a $2 million portfolio across four properties, 40% equity, a 5.5% mortgage rate, a 5% gross rental yield, and 25% operating costs excluding interest. Under current law, with full deductibility, that portfolio nets roughly $9,000 a year in cash profit, taxed at a landlord's marginal rate. Remove the interest deduction and nothing about the cash flow changes - the same $66,000 in mortgage interest still leaves the landlord's account every year - but the taxable profit jumps from $9,000 to $75,000, because the interest can no longer be offset. Stack that on a $150,000 personal income and tax it at the Green Party's proposed rates, and the tax bill comes to roughly $32,600 a year, on a portfolio that only generates $9,000 in actual cash profit. The landlord ends up paying tax out of pocket, not out of rental income.

What About the Wealth Tax? Does It Actually Affect Most Landlords?

No, for almost everyone reading this. Only the Green Party has proposed a wealth tax; National, ACT, NZ First, Labour and Opportunity have not. The Green policy applies a 2.5% annual tax to net worth above $10 million as an individual, or $20 million as a couple, with the family home excluded entirely. A landlord with a handful of rental properties and, say, $800,000 in equity across their portfolio is nowhere near that threshold. The real cost to a typical landlord under the Green Party's package comes from the interest deductibility removal and the new top tax bracket, not the wealth tax that gets most of the headlines.

What Happens to Capital Gains If I Sell?

This only matters at the point of sale, and it depends entirely on which party's policy applies at the time. National, ACT and NZ First keep the current 2-year bright-line test, so a property held longer than that owes nothing on sale under any of them. Labour's 28% capital gains tax applies regardless of how long the property was held, on gains accrued after 1 July 2027, with the family home excluded. The Green Party's extended 10-year bright-line test taxes a sale inside that window as ordinary income at their proposed rates, which could mean paying up to 45% on the gain rather than a flat 28%. Opportunity has no capital gains tax and no bright-line test at all - having replaced both with its ongoing land tax - so a sale under Opportunity's policy triggers no separate tax event on the gain itself.

Run Your Own Numbers

Every figure above uses a single illustrative example. Your own portfolio size, equity, mortgage rate, rental yield, and personal income will change the result, sometimes significantly. The calculator above lets you enter your own numbers and see the same six-party comparison, including the one-off tax on sale if you're planning to sell, calculated live as you adjust the sliders.

What If a Party Changes Its Policy Before the Election?

We'll update this article and the calculator above as parties confirm, change, or add policies that affect landlords between now and election day, and note what changed here. The numbers on this page are a snapshot as of 30 August 2026, not a forecast, and election-year policy moves quickly.

Bookmark this page, and share it with any other landlord it's relevant to. Every party's numbers will keep moving between now and 7 November, and having the current comparison on hand, for your own portfolio, is worth more than remembering today's figures from memory.

None of this is voting advice. It models the direct tax and cash-flow effect of each party's own stated property policy on a rental portfolio, nothing more, and nothing about a party's wider platform, its chances of entering government, or what it might negotiate away in coalition talks. RentManager NZ has no party affiliation, no conflict of interest, and was not paid by any party or candidate to publish this.

If keeping track of the numbers behind your own portfolio - rent, mortgage payments, and what's actually left after tax - is something you're doing by hand or not at all, register for a free RentManager account and let the property dashboard do that tracking for you automatically, on your own numbers, not the illustrative example above.