There are fresh worries for Labour following the latest ONE News Colmar Brunton poll.

The party has slipped three points to 26 per cent. That's the lowest it's been in the ONE News poll since the last election when it recorded 25 per cent.

National, however, remains in fine form riding high, steady this month at 48 per cent, the same result it picked up on election night in 2014.

The Greens are trucking along solidly up one per cent to 13, although the big mover is New Zealand First which is up to two points in our poll to 11 per cent. The Maori Party has also had a small gain up one, to two per cent.

On these numbers National would be able to form a government using its existing support partners, assuming that is Peter Dunne and Act's David Seymour win their seats.

Labour and the Greens, even with New Zealand First on board, would fall short.

There is some slightly better news in the Preferred Prime Minister stakes for Andrew Little. He's up three points to 10 per cent.

However he's still below Winston Peters who has slipped one to 11 and Prime Minister John Key who is way out in front on 38 per cent, down one this month.

Labour has been quick to attack the poll, leader Andrew Little saying the poll is "bogus" and he doesn't accept it. He says he has seen other polls that tell a completely different story.

Source: Breakfast

Mr Key says the poll is good for National and partly reflects the fact Kiwis are becoming increasingly optimistic about the strong economy.

Forty-five per cent of Kiwis polled in the survey think the economy will get better over the next 12 months, up three per cent on June.

The numbers that think it will get worse are down from 36 to 31 per cent.