National's fallen back from its 50 percent support in the latest Roy Morgan opinion poll, but remains well out in front of other political parties.

The party's fallen four and a half points to 49 and a half percent support in the latest survey.

That gives it a 23 and a half point lead over Labour which has risen half a point to 26 percent.

The Greens have gained two and a half to 13 percent, New Zealand First's on six and a half percent.

The Maori Party, ACT, and United Future are all on one percent or lower