Prime Minister Jacinda Ardern has blasted National leader Todd Muller for "spreading blatant misinformation" by associating Labour with the Green Party's tax policy.
The Greens have proposed guaranteed minimum income of at least $325 a week by introducing higher tax brackets. The Greens also want a 1 percent tax on net assets over $1 million and 2 percent over $2 million, excluding housing wealth under mortgage.
Labour has not yet released its tax policy and Ardern is not ruling out introducing higher tax brackets as the Greens have proposed. The National Party has jumped on it, launching attack ads that infer a Labour-Greens coalition post-election.
"Labour-Greens plan to tax your house, your retirement fund, your business assets, and even your art. Who knows what they'll tax next?" a National Party ad posted on social media said before showing a picture of a golden labrador suggesting Labour would tax dogs.
Muller asked the Prime Minister in Parliament on Wednesday if she could rule out introducing the proposals put forward by the Greens.
"I am not responsible for other parties' tax policies... nor has Labour released its own," she said. "When we have, I'm happy to debate it. In the meantime, I urge the member not to continue to spread the blatant misinformation to New Zealanders that he has to date."
Muller asked Ardern if she supports the Green Party's policy of introducing a wealth tax.
"I am happy to clarify for that member again - because he seems to have missed this in all of the advertisements I've seen the National Party put his name and reputation on - that is not our policy," Ardern said.
"It is another party's policy, just in the way ACT's flat tax rate I only assume is not the National Party's policy."
Muller again asked the Prime Minister if she will rule out a wealth tax.
"[You] only need to look at our reputation in this House. We have not introduced any such tax. I am not responsible for any other party's tax and in this House I therefore will not be answerable to another party's tax policy."
The Prime Minister questioned the Greens' policy earlier this week saying it had some "fairly heroic assumptions" - but she did not expand on what parts of the policy she thought were assumptions.
Currently, every dollar earned over $70,000 is taxed at 33 percent - the highest tax bracket. But the Greens want everything over $100,000 taxed at 37 percent and anything over $150,000 at 42 percent.
National's finance spokesperson Paul Goldsmith said on Tuesday Labour was "desperate" to increase taxes and doubled down on Wednesday by describing Ardern and Robertson as "slippery" on tax.
"Labour plans on spending as much as it takes in an attempt to keep their poll numbers high until the election, and on September 20 the smiles will drop and New Zealanders will be presented with the bill."
He said National wouldn't introduce any new taxes in its first term if it wins the election.