A new poll records another boost for a future Labour-Greens coalition.

The latest Roy Morgan sees a 1 per cent rise in support for a potential alliance between the two parties.

Support for the Labour party was unchanged (37 per cent) from the last poll a fortnight ago. The Greens rose to 12.5 per cent - up 1 per cent.

National was down slightly - 0.5 per cent - to 41.5 per cent. Its coalition parties were largely unchanged: the Maori Party was on 1.5 per cent (up 0.5 per cent), ACT 0.5 per cent (unchanged) and United Future 0 per cent (down 0.5 per cent).

The last Roy Morgan poll, held in the wake of the election of new Labour leader David Cunliffe, saw that party registering its highest popularity since Helen Clark was prime minister.

Pollster Garry Morgan said a Labour/Greens ticket would win easily if an election were held today.

He said Cunliffe has "re-invigorated" Labour, which sat just 4.5 per cent behind National.

NZ First rose slightly to 5 per cent, the Conservative Party (0.5 per cent) took a 1.5 per cent hit. Mana was unchanged on 0.5 per cent.

Roy Morgan polled 839 voters between September 30 and October 13.

Confidence in the government also fell with 55 per cent (down 4 per cent) saying New Zealand is heading in the right direction, compared to 31 per cent (up 1.5 per cent) who listed the wrong direction.