A majority of MPs from both major parties could be personally affected by the introduction of a capital gains tax on properties they own apart from the family home.
The 2018 Register of Pecuniary Interests, which lists all properties MPS have declared an interest in, shows three-quarters of National MPs have an interest in two or more properties. Among Labour MPs, the figure is two-thirds.
Among the smaller parties, two-thirds of New Zealand First MPs have an interest in two or more properties but only one Green MP does. Act leader David Seymour owns no property.
Sir Michael Cullen's Tax Working Group has recommended the Government implement a capital gains tax (CGT).
It would cover assets such as land, shares, investment properties, business assets and intellectual property. The family home would be exempt.
The CGT, which would apply from April 2021 and only on gains made after that date, would see realised capital gain added to income, meaning most of it would probably be taxed at the top tax rate of 33 per cent.
National and New Zealand First have long been against the idea of a capital gains tax, although New Zealand First will have to get on board with some kind of CGT model as part of the Coalition Government. The Green Party and Labour both support a capital gains tax for properties other than the family home.
The 2018 Register of Pecuniary Interests lists all properties MPS have declared an interest in. The register is the most up to date information available but does not show any properties sold or bought in the year since it was produced. It also does not specify how large land sections are, the current value of the properties, or the date they were bought.
In some cases, MPs are trustees and/or beneficiaries of trusts in which properties are held, or the properties are owned by superannuation schemes.
National's Amy Adams, the party's finance spokeswoman, has interests in eight properties, all in trusts. They include a farm in Canterbury, land in Waikato and Canterbury, two South Island commercial properties and another three residential properties.
Adams told the Herald two had since been sold.
She said she was in the position she was in partly because her mother, who came from "absolutely nothing" and was a solo mother-of-two, wanted to leave something for her children.
"She did leave us something when she died and as a result, some of the properties I've had are because of my mother working so very hard all her life. For anyone to suggest that disqualifies me from having a view or standing up for the rights of New Zealanders who have worked hard and just tried to get ahead is an absolute gutter and cheap tactic.
"I have always paid every dollar of tax that I've been required to pay and I always will. My position is that this tax is one that will be bad for New Zealand," Adams said.
National leader Simon Bridges has four properties according to the register - three residential properties in Tauranga, Auckland and Wellington, and a commercial property in Tauranga.
His family home has an RV of $2.29m.
His deputy Paula Bennett is listed as having an interest in three properties, a townhouse in Mt Eden, her primary residence in West Auckland and a house she jointly owns with her parents.
National's housing spokeswoman Judith Collins is listed as having interests in her family home in Auckland, a commercial and residential property in Wellington and a residential property in Nelson.
Collins is listed on a number of titles according to QV but that is because of her former work as a tax lawyer as a non-beneficiary trustee.
Collins said if she went back to that profession, a capital gains tax would be a "great boost" to her income.
"I know the cost and what it actually takes to bring in new taxes that particularly target an area."
Prime Minister and Labour leader Jacinda Ardern is listed as owning only a family home in Sandringham with a registered valuation of $1.75m. A CGT would not apply to any gain that she and her partner Clarke Gayford made on that property because it is their primary residence.
Deputy Labour leader Kelvin Davis owns only his family home in Kaitaia while fellow Labour MPs Finance Minister Grant Robertson and Housing Minister Phil Twyford also own only a family home each.
New Zealand First leader Winston Peters owns a home and land in Whananaki, Northland, with an RV of $1.58m, and a property in St Mary's Bay in Auckland.
Deputy leader Fletcher Tabuteau jointly owns a home in Rotorua and an apartment in Thorndon, Wellington, plus his family superannuation scheme owns another apartment in Wellington city.
Defence Minister Ron Mark has a family home in Carterton and a unit in Petone owned by a trust, a leasehold property in Christchurch and "numerous" blocks of Māori land.
Regional Economic Development Minister Shane Jones has five homes listed on the register.
Some of them were properties that had been in the family a long time that were unlikely to be sold and his children lived in them, he said.
"Whatever the law is at the point of transaction, as a public figure Matua Shane will obey the law. But I don't want to reflect one way or the other my zest or otherwise for the tax proposals. "
Green Party co-leader James Shaw is listed as a joint owner of a family home in Wellington. The RV for his home was not available. His co-leader Marama Davidson rents her Manurewa home. Fellow Green MP Associate Transport Minister Julie Anne Genter is listed as owning an apartment in Wellington.
Green Party MP and Conservation Minister Eugenie Sage jointly owns her family home at Diamond Harbour near Christchurch as well as a residential section in suburban Beckenham and rural land on the West Coast.
Sage told the Herald she would be "more than happy" to pay a capital gains tax.
"I would be contributing my fair share towards services that help our community thrive, like schools and hospitals," she said.
Act leader David Seymour is listed as owning no property.