Deputy Prime Minister Bill English says National's strong lead in the polls is likely to diminish when people start focusing on the November 26 elections.
Two polls released on Sunday showed National holding enough of the party vote to govern alone - something that hasn't happened since MMP was introduced in 1996.
Labour was at a 15-year low in a 3 News-Reid Research poll, dropping 2.2 points to 26.6 per cent, while National was up 3.5 points to 57.4 per cent.
Labour had a slightly better result in a One News Colmar Brunton poll, dropping one point from the previous poll to 29 per cent while National was steady on 56 per cent.
"That gap is almost certainly going to close," Mr English said on Monday.
"People haven't been focused on politics recently.
"In the last month before the election there's going to be an intense campaign, and when New Zealanders focus on it they always pull a government back a bit."
Mr English said the government was going to focus on telling the public the things it had to do to get the economy moving and producing more jobs and higher incomes.
"The issues are pretty clear - a more competitive economy and getting back into surplus," he said on NewstalkZB.
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