Increasing support for Labour and the Greens means a coalition would easily win a snap election, a poll suggests.
A Labour/Green coalition would easily sweep into power if an election were held today, even without people knowing who the Labour leader will be, a poll suggests.
A Roy Morgan poll, released on Friday, put support for Labour at 32.5 per cent, up 1 percentage point on last month's poll, and the Greens at 15 per cent, up 1.
Their combined tally of 47.5 per cent outstrips that of National, which has slipped 3 points to 41 per cent.
National's coalition support partners are little changed, with the Maori Party at 1 per cent (down 1), Act 1 per cent (up 0.5) and United Future 0.5 per cent (unchanged).
However, 6 per cent of those surveyed didn't name a party, which was a high proportion.
Pollster Gary Morgan says the results show whoever emerges as the new opposition leader on Sunday "stands a good chance of becoming New Zealand's next prime minister as the head of a left-leaning alliance".
The two-week polling of 828 electors started four days after David Shearer stepped down as Labour leader on August 22.
Since then, contenders Shane Jones, Grant Robertson and David Cunliffe have made their cases for Labour's top job, and the winner will be announced on Sunday.
The Labour/Green poll lead over National is the biggest since April.