Key Points:

A grim election forecast for Labour continues in the latest poll sampling the party vote.

Today's Fairfax Media poll by AC Nielsen shows National winning 54 per cent of the party vote against Labour's 30 per cent. In a poll in May National attracted 56 per cent and Labour 29 per cent.

The latest poll gives the Green party seven per cent, NZ First three per cent, Maori Party two per cent, Act and United Future both attracting one per cent.

The poll shows National 24 percentage points ahead of Labour.

National leader John Key remains the preferred prime minister by 43 per cent of voters to Helen Clark's 30 per cent, though another 20 per cent say they don't know whom they prefer.

The poll shows 37 per cent of voters would view a change in leadership as doing more harm than good to Labour's prospects, while 33 per cent think it would make no difference.

The poll questioned 1101 people over seven days up to last Tuesday and had a margin of error of 3 per cent.