Labour has tumbled three points, National has fallen two and neither party could form a Government without New Zealand First, tonight's One News Colmar Brunton poll shows.
New Zealand First and the Green Party are both up two points on the May poll after the Budget, to 11 per cent apiece.
Labour leader Andrew Little and Prime Minister Bill English are both down by three points as preferred Prime Minister and New Zealand First leader Winston Peters is up by four points.
But Little, the leader of the Opposition, is the fourth preferred Prime Minister, with his own deputy, Jacinda Ardern, polling ahead of him, as well as English and Peters.
The Maori Party is up to 2 per cent, and Gareth Morgan's Opportunities Party is steady on 1 per cent. Act recorded 1 per cent and United Future don't feature.
National 47 per cent (down 2)
Labour 27 (down 3)
Greens 11 (up 2)
NZ First 11 (up 2)
PREFERRED PRIME MINISTER
Bill English 26 per cent (down 3)
Winston Peters 11 per cent (up 4)
Jacinda Ardern 6 per cent (steady)
Andrew Little 5 per cent (down 3)
If translated to votes, and if the Maori Party, Act and United Future kept their electorate seats, the parties would have the following seats in a House of 122: National 57, Labour 33, Greens 14, New Zealand First 14, Maori Party 2, Act 1 and United Future 1.
Under that scenario, National would not be able to form a Government with its current support partners, Act, United Future, and the Maori Party. It would be short by one seat. But it would be able to do so with New Zealand First.
Labour would not be able to form a Government with only the Greens and New Zealand First. It would also be short by one. It would also need the Maori Party.
Peters is on a regional tour of New Zealand at present ahead of his party conference this weekend in Auckland.
English today listed a series of regional visits and announcements the Government is planning this week, but at his post-Cabinet press conference he denied it was in response to Peters' regional activity.
"I'd suggest the opposite," he said.
Peters' activity in the regions was a response to the Government having been working with them constructively for several years, English said.
"He'll be finding that their economies are a good deal more robust and growing well compared to what he was saying.
"So no, we are not sensitive at all. Mr Peters has now found the map. He is out there discovering these places. We've been there working for a long time."
Commenting on the stoush between the Green Party and Winston Peters after Green co-leader Metiria Turei accused him of having "a very racist approach to immigration" during a weekend interview (Q+A, TV1), English said: "It just makes it pretty clear that the proposed Labour Greens New Zealand First coalition would be inherently unstable because their internal differences are deep."
Little told One News he was not particularly concerned about his numbers and there would be no change in leadership.
"The party is absolutely humming," he said.
The dip for both Labour and National has occurred after both parties were engulfed by controversies, English over his handling of the Todd Barclay secret recordings, and Little over the scheme to bring in 85 foreign interns to help Labour campaign.
The poll of 1007 eligible voters was conducted July 1 - 5. It has a margin of error of plus or minus 3.1 per cent. Party vote undecideds stood at 19 per cent (up 2).