John Key believes New Zealand First is benefiting from Labour's loss of support.
LISTEN ABOVE: PM John Key speaks to Mike Hosking
Labour has fallen to 26 percent support in the latest One News Colmar Brunton poll.
John Key told Mike Hosking Labour's marriage to the Greens has seen it lose support from those in the centre right.
"We see it in our numbers, Labour are losing support a little bit to us, but mainly to New Zealand First."
"Our voters are changing, to be frank our vote has been amazingly consistent."
However, Labour leader Andrew Little said a poll that shows his party has slumped to just 26 per cent doesn't stack up with other recent surveys.
"There have been two other recent polls that I have seen that have shown completely different results," he said on Tuesday.
"And there was one published two or three weeks ago that was even better than our internal polling."
Meanwhile, Key told Mike Hosking he doesn't think Fiji's Prime Minister Frank Bainimarama is spoiling for a fight.
Frank Bainimarama boycotted the Pacific Forum meeting, calling for New Zealand and Australia's expulsion from the regional organisation.
Last week a number of opposition leaders, unionists and academics were arrested for criticising Fiji's constitution during a panel discussion.
Key said "when you get to the place of being Prime Minister through a military coup, even if you win a democratic election you have to adjust your thinking."