A poll conducted internally for the Labour Party sees New Zealand First overtake the Green Party.

Winston Peters' party is on 14 percent while the Greens sit just below on 13 percent.

It means New Zealand First, for the first time in three years, is no longer the lower rating party.

The poll, which would not normally be made public, has Labour on 26 percent, down from 34 percent in May.

National is still out in front on 42 percent.