A Labour/Green/Maori Party coalition would have the edge over other parties in a tight race to form a government, according to a new poll just a week out from the election.
Following divergent poll results this week, the Roy Morgan survey of 866 voters indicates Labour could get 49 seats, the Greens 11 and the Maori Party two for a total of 62 MPs in a 120-seat parliament.
Current ruling party National would get 50 seats, NZ First seven and the Act Party one for a total of 58.
Support for Labour had risen 7 per cent from mid-August to 39.5 per cent while National's support had dropped 2.5 per cent to 40 per cent.
The momentum was clearly with Labour and its leader of seven weeks, Jacinda Ardern, says Roy Morgan chief executive Gary Morgan.
"However, the narrow gap between the major parties means the final outcome of the election will be decided by the second string parties - and it is here that Labour has a decisive edge."
The Greens had held steady on 9 per cent over the past month.
Ms Ardern's vow to cut net immigration by up to 30,000 appeared to have significantly dented support for the traditionally anti-immigration New Zealand First, which was down 5.5 per cent in a month to 6 per cent, Mr Morgan said.
Earlier in the week, separate polls indicated contrasting results for the September 23 election.
Tuesday's Newshub Reid Research poll indicated 47.3 per cent support for National and Labour losing 1.6 points to 37.8 per cent. The Green's 4.9 per cent support wouldn't be enough to get back into parliament and National could have 61 seats in a 121-member parliament.
Thursday's 1News Colmar Brunton poll showed Labour up one point to 44 per cent and the Greens gaining two points to 7 per cent, translating to a coalition 63-seat majority.