Labour deputy leader Kelvin Davis says he's not sure if Labour will introduce a capital gains tax in its first term, or campaign on it at the 2020 election.
The party has been coy about its tax plans, leader Jacinda Ardern consistently saying if it's elected, a working group would be formed to figure out the details.
The only guarantees so far have been no capital gains tax on the family home, and no income tax hikes.
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Asked if a capital gains tax could be introduced before the next election, Mr Davis admitted not even Labour knew that.
"Look, I'm not going to answer that question because right now, I don't know," he told The AM Show on Friday.
"We've got to have the tax working group make their decisions, and we'll come to the country with whatever they produce."
Deputy Prime Minister Paula Bennett, also on The AM Show, said Labour's had a decade to figure out what its CGT policy is.
"If you want to be running the country, you've got to have answers. The public deserves that."
National, when it was elected in 2008, also tasked a working group with making suggestions. The party then increased GST, breaking an election promise from then-leader John Key.
Mr Davis says the current tax system isn't working for most New Zealanders.
"There was a report in 2012 that said of 161 high-income New Zealanders with assets of over $50 million, 107 of them said that their income was $70,000 or less. We've got to sort out the whole tax system."
An Oxfam report earlier this year citing IRD figures said a third of the 252 Kiwis worth more than $50 million had a declared income below $70,000 - so weren't even paying the top tax rate many salaried workers do.
"What we have now is an unlevel playing field where high-wealth New Zealanders with assets of over $50 million are claiming income of less than $70,000, and that's wrong."
Mr Davis claimed National has introduced 16 new taxes in the past nine years. Newshub has contacted Labour for clarification on what it believes these taxes are.
Confusion on KiwiBuild
Mr Davis was also quizzed on Labour's KiwiBuild plan, which aims to have 100,000 affordable homes erected in 10 years - half of them in Auckland.
He claimed that would mean 30,000 built in the first three years.
"It would be around about 30,000 houses... wouldn't it? Ten thousand a year on average."
But that's not what Labour has said in the past. Former leader Andrew Little told The AM Show in February it was unrealistic to expect that KiwiBuild to hit its targets from the get-go.
"It won't be 30,000 - it'll be closer to 20,000, because you're ramping up," said Mr Little. "Once you've had that kind of three-year ramp-up period, then you're going gangbusters."
He's not alone in getting housing numbers wrong, though. During Thursday night's Leaders' Debate, Prime Minister and National Party leader Bill English said 10,000 new homes were built in Auckland in the past 12 months - the actual figure is around 6700.
"I think it was more the building consents," Deputy Prime Minsiter Paula Bennett told The AM Show on Friday - admitting she didn't know the exact numbers either.
"So if he got that one slightly wrong, then he might have. I haven't seen that stat."
She then said Labour was only planning to build 1000 new homes, seemingly confusing the party's plans to use Housing NZ dividends to build social housing with its separate KiwiBuild scheme.
Ms Bennett says National will build 2000 new state homes a year, but it's not clear if this is a net figure accounting for any the party might sell.