Bill English has defended the confrontational approach his party has taken against Labour and NZ First since the coalition took power, saying they're simply doing their job as opposition.
"They want to run the country? They should be able to run Parliament," the National Party leader told Three's The Nation.
"It's an odd Government and basically a weak one.
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"The fact is... in Parliament we have more seats than NZ First and Labour put together. But that doesn't mean we pack our bags and cry in our milk for two years."
Mr English said "the public can see" the "shambolic" start Labour has had.
"In fact we don't need to point it out," he said.
"The things that are likely to work are where they pick up the policies in place... and develop them further.
"But the early indications are they're disorganised and relying on the crutch of a big chequebook."
But Mr English denied leaving the coalition a struggling economy to work with.
As NZ First leader Winston Peters announced he would go into a coalition with Labour, he said there were "dark days ahead" both on the international horizon and here.
Prime Minister Jacinda Ardern also previously told The Nation that it needs to be acknowledged the market economy has "failed out people in recent times".
"How can you claim you've been successful when you have growth roughly three percent, but you've got the worst homelessness in the developed world?"
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But Mr English is unrepentant.
"I don't make any apology for the performance of the economy over the last wee while," Mr English said.
"The productivity issue, I think, was clouded with a whole lot of sort of half-baked information and slogans. But actually, by international standards, productivity was pretty good.
"We've got thousands of people came off welfare, we've absorbed thousands of people into the construction industry - that has some impact on productivity because they're not necessarily high productivity industries."
Mr English said the Government needs to "get to grips" with the fact their job is to support confidence in economy, "not talk it down".
The half-yearly Economic and Fiscal Update will be released next week