'Never promise a tax before election': Winston Peters blames Labour for National's high results

New Zealand First leader Winston Peters has hinted he could reverse his call for a referendum on Māori seats in Parliament.

It would remove one of the main barriers to a coalition with Labour.

On Wednesday, Mr Peters has made it very clear what he thinks of the media, launching a war on journalists at a press conference.

But he was happy to talk to one across the ditch - Andrew Bolt of the Bolt Report.

"Some people asked me, 'Why are you going on the Bolt show'. The guy actually had me on his show before the election," Mr Peters said in the interview.

Talking on Sky News Australia, the king - or queen-maker revealed much more about his plans than he would at a press conference full of New Zealand journalists.

Mr Peters also adopted the role of political analyst, saying National only came out on top because of Labour's tax fail.

"They got home in a campaign which was seriously affected by what you might call a couple of blunders from the other side," he said.

"You never promise a tax before the election."

He even engaged in a partial backdown on his promise of a referendum on the Māori seats.

"Some of the things or the elements to the environment which the promise was made have changed," he said.

It's an important development as it's the only bottom line of Mr Peters' that either side has ruled out, with Jacinda Ardern very staunch about it.

The promise was made in July at his party conference - so what's changed?

"The race-based, origin of race party, got smashed in this election and is gone," he said.

Along with his referendum backdown, he also revealed that he won't be holding any grudges against the person or party which leaked his pension overpayment details.

"I can't let it influence my judgement because I'm meant to be acting in interest of everybody," he said.

And while he doesn't want to talk about bottom lines, he was happy to lay down a promise he expects from either side.

"I want them to promise they've got a grasp of economic reality," he said.

The backpedalling on Māori seats doesn't signal Mr Peters will pick the red team but it does remove one large barrier to forming a coalition Government with Labour - a symbolic gesture that should not be taken lightly.