Finance Minister Grant Robertson won't cut 'core' spending if economy tanks

New Finance Minister Grant Robertson is backing up Jacinda Ardern's view the economy has been a "blatant failure" when it comes to helping New Zealand's most vulnerable.

Ms Ardern made the comments on The Nation a week ago, two days after finding out she'll be the country's next Prime Minister.

"If you have hundreds of thousands of children living in homes without enough to survive, that's a blatant failure. What else could you describe it as?" she told host Lisa Owen.

Mr Robertson told The Nation on Saturday the "days of a hands-off, laissez-faire Government hoping for the best for New Zealand are over".

"What Jacinda Ardern has said is if you've got the world's worst homelessness, then the form of capitalism that we've seen in New Zealand isn't working for those people - and I would agree with that," he said.

"That's the foundation principle of the Labour Party… we believe in the fact there is an obligation on Government to help ensure fairness, to make sure everybody gets a chance to achieve their potential."

To fix it, he - like Ms Ardern - says Labour will lead an "active" Government "that partners in the regions with local government, with business, with iwi". But he appears to want to avoid the 'nanny state' accusations that plagued Labour's last administration under Helen Clark.

"That's a different thing entirely from meddling and telling people what to do. We actually want to listen."

The last Labour Government ran nine consecutive surpluses, albeit in good global economic conditions. In his speech announcing who would form the next Government, NZ First leader Winston Peters warned of "dark days" ahead.

Mr Robertson said he would rather borrow than cut spending, if those "dark days" arrived.

"I came into politics to make sure that we provided better opportunities for New Zealanders, that we protected our most vulnerable. There are certain areas of spending that we must do to be a decent society, to care for other people. I would never compromise on that."

He praised the National-led Government for continuing to spend during the global financial crisis.

"They made sure those core areas of spending carried on - that's what responsible Governments do."

Ex-Finance Minister Bill English posted a number of deficits through the global financial crisis, with the economy picking up enough to post thin surpluses during National's third term.

Mr Robertson is confident Mr Peters' "dark days" won't happen.

"I don't think we're going to need to have that conversation."