A new poll shows National has almost double the support Labour has.
The poll, taken by Fairfax Media Research International, gives National 56% of the party vote and Labour 29%.
The Greens have 6%, while no other party has more than 2%.
In the preferred prime minister stakes, John Key is on 53% and Phil Goff on 6%.
The poll of 1004 eligible voters was taken last week, after Labour had released details of its plan for a capital gains tax.
It has a margin of error of 3.1%.
