The Fairfax Media-research International Poll shows National with 56 percent support while Labour languishes on 29 percent support -- its worst result in 15 years.
Translated to seats in Parliament, National would have 71 MPs after November's election.
The Green Party has 6 percent support, while ACT and NZ First each have 2 percent.
United Future, Mana and the Maori Party all have 1 percent support or less.
When it comes to leader support, John Key records 53 percent as preferred prime minister, compared with Labour leader Phil Goff who has 6 percent support.