A new Roy Morgan political survey shows the Government taking a big hit with National down 3.5 points from the previous survey last month to just 40.5 per cent .
Support for Labour was up one percentage point to 35.5 per cent and the Greens edged up slightly to 13.5 per cent in the poll.
It is the smallest gap between the two big parties in the poll since just before the 2008 election that swept Helen Clark's Labour Government out of office.
The numbers this time, though, are enough to give a Labour-Green coalition the seats it would need to govern.
Backing for Prime Minister John Key's support parties was little changed with the Maori Party on 2 per cent (down 0.5), ACT unchanged on 0.5 per cent and United Future on 0.5 (down 0.5).
NZ First climbed 2 percentage points to reach the 5 per cent MMP threshold for list seats.
Mana was on 0.5 per cent (unchanged) and the Conservative Party was up slightly at 1.5 per cent.
Opposition parties took 54.5 per cent of the vote while backing for government parties totalled 43.5 per cent.
The numbers for the three biggest party are in line with internal polling by Labour, a source said. But the party has been reluctant to publicly release the data, waiting first to see it the shift away from National is confirmed by two polls expected this weekend from TV3 and TVNZ.
The survey of 879 was taken between April 1 and April 14.
The latest NZ Roy Morgan Government Confidence Rating is down 3.5pts to 116 with 51.5 per cent (down 2 per cent) of New Zealanders saying New Zealand is 'heading in the right direction' compared to 35.5 per cent (up 1.5 per cent) that say NZ is 'heading in the wrong direction'.
Should the speed limit be raised to 110kmh on some roads?Related story: 110kmh limit moves closer