David Seymour and Paul Goldsmith have come out swinging against the Green Party's "transformational" proposal to tackle inequality and reform welfare.
Released on Sunday in the lead-up to the election, its Poverty Action Plan would introduce wealth taxes and new high-income tax brackets to pay for a guaranteed minimum income of at least $325 a week.
The income taxes would kick in at 37 percent at $100,000 and 42 percent at $150,000. There would also be a 1 percent tax on net assets over $1 million and 2 percent over $2 million - excluding mortgaged houses and household goods worth less than $50,000.
But ACT Party leader Seymour warns this will send New Zealand in the wrong direction.
"At a time when we need to get New Zealanders back to work, the Greens want to suck the life out of the economy by taxing successful people harder and creating even more welfare dependency," Seymour told Newshub.
"This kind of European socialism will only prolong the economic pain."
And National's Finance spokesperson Goldsmith says we need our small businesses to invest and create more jobs - not tax them more.
"Rather than celebrating Kiwis doing well, the Greens seem to want to punish them," he says in a statement.
"National has committed to no new taxes for Kiwis in our first term.
"While the economy is going down, the Greens want to tax us more, and Labour haven't ruled out doing the same."
However Greens co-leader Marama Davidson has been blunt about the need to tax the rich more.
"We have enough for everyone to live with dignity, but the system is rigged so a few have more than they will ever need, while far too many will always struggle. It is time to change this," she said on Sunday.
"Those who have large amounts of wealth are not asked to contribute to help everyone else. This hole in the tax system has allowed most of Aotearoa's wealth to accumulate with a small number of people."
