National has refused to rule out Act Party policy that would see a number of ministries given the axe.
Christopher Luxon says those conversations will be had next year.
Finance Minister Grant Robertson says the public have a right to know where the two potential coalition partners sit.
"The only way on polling that I've seen that National could be in government is with Act, therefore they have to front up to New Zealanders to tell them which of Act's policies they'll accept," Robertson said on Tuesday.
Under Act's alternative budget released this week, it would abolish the Māori Development Minister, Ministry for Pacific Peoples, Ministry for Women, Ministry for Ethnic Communities, and the Human Rights Commission.
"I very seldom find someone that can point to anything concrete that they've done," Act leader David Seymour said.
"We shouldn't have ministries that are there just for a type of person because every ministry should be serving every type of person."
It's not just ministries Act would get rid of, saying it would also cut around 14,000 jobs in the public sector.
Luxon is partly on board with the idea.
"I think there's a very good point in there. I think we have over the period of this Government built a huge amount of bureaucracy."
However, Luxon would not be drawn on questions over abolishing ministries.
"I'm not interested in talking about the Act policy about what they would do in a budget.
"As I said to you that's not this year, we'll deal with that next year."
Threatening the Ministry of Māori Development earned Seymour a verbal assault from his fellow Māori MPs.
Māori Development Minister Willie Jackson leading the charge.
"He's just a useless Maori that's all," Jackson said.
"David's a disgrace to be quite honest," Māori Party co-leader Rawiri Waititi added.
"That's not even a secret," said Green co-leader Marama Davidson.
Seymour dismissed the criticism. "All the name calling and all the rest I think is a shame," he said.
It comes as Luxon on Tuesday confirmed his deputy Nicola Willis would be finance minister in any future Government, drawing quick criticism from Act.
"I think he's come to that prematurely quite frankly," Seymour said.
But Luxon remains adamant.
"I am making a concrete promise, I am having Nicola Willis as our Finance Minister there's no doubt about that," he said.
It prompted a further response from Seymour.
"Yeah well it's a promise that he can't actually keep cos he doesn't actually know what the election results are," he said.
Leaving plenty for the Opposition to iron out, in any possible future coalition.