The Finance Minister says Labour's GST policy isn't to blame for its latest slump in the polls.

The latest 1News Verian results puts Labour on its worst numbers in 6 years - tumbling 4 points - to just 29 percent.

National has climbed two points to 37 percent, which gives the party support to form a Government with ACT's 13 percent.

The research was conducted right after Labour announced it will remove GST from fresh fruit and veg.

But Grant Robertson says he doesn't believe this is driven by one single policy.

"It's been a challenging time over a period of months, but we've got 2 months to let people know what's at stake here- and I think it is a hugely important election for New Zealand."

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