With seven months to go to the general election the race has tightened a bit, according to the latest political poll.

National is down four points to 46 per cent in a Colmar Brunton poll for One News.

Labour is up 2 points to 30 per cent, the Greens are unchanged on 11 per cent and New Zealand First is up a point to 11 per cent.

National would fall short of power with its current partners based on the poll result.

Prime Minister Bill English is on 31 per cent in the preferred prime minister measure, five points below the level John Key had in the previous poll in November when he was prime minister.

It's the first Colmar Brunton poll since Mr English became prime minister.

The poll was taken between February 11 and 15.