Deputy Prime Minister Carmel Sepuloni has unleashed on National and ACT, calling the right-bloc parties "not the best managers of the economy".
She referred to the parties as a "coalition of cuts" - a line commonly used by Labour in recent weeks - and again questioned how National would fund its policies like index tax thresholds to inflation.
It comes as Labour's election campaign unofficially gets underway, with party members gathering in Wellington for its congress at Te Papa.
Labour has come out swinging ahead of the conference, claiming New Zealanders could miss out on up to $100,000 under a right-bloc Government due to National's policy of raising the superannuation age to 67 and ACT's plan to scrap KiwiSaver subsidies at $65,000.
"We lost about $24 billion when the previous National Government decided to stop contributing [to superannuation]," Sepuloni said in an interview with Newshub Nation on Saturday.
"I think that's a very clear indication that they are not the best managers of the economy."
The National Party's policy on superannuation remains unchanged from what former Prime Minister Sir Bill English announced in 2017, that the age of eligibility would be phased from 65 to 67 starting on July 1, 2037. That was to reflect increasing life expectancies and the rising cost of the scheme.
Prominent economist Shamubeel Eaqub has called for a couple of steps further. He wants the age to be raised to 70 and for it to be means tested so the wealthy don't get it.
Sepuloni went on to say New Zealanders wanted "to be supported when they go into their retirement".
If elected, National has also said it would index tax thresholds to inflation - but it had received some criticism for benefitting those on higher incomes more than the lowest earners
Sepuloni said she couldn't see how National could fund its tax policy when the party "hasn't said what they would need to cut in order to provide those tax cuts".
"I think we need a little of public transparency and honesty with the general public because New Zealanders deserve to know what they will be giving away - and that may include superannuation if they're getting tax cuts," she said. "I think we really need to disspell this myth that's out there that National are good at managing the economy."
Meanwhile, a policy will be announced by Sepuloni, who has the social development portfolio, later on Saturday morning. However, the Government only released the Budget last week - therefore any policy announcements made this weekend were unlikely to be major.
"I don't want to announce the policy now," Sepuloni told Newshub Nation when asked to divulge in what the announcement would be.
"It's important that we have an opportunity to share that [policy] with the party members that are here, and so you're going to have to wait a little while," she told host Simon Shepherd.
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