Simon Bridges says it would be "silly and pointless" to put his leadership to a vote.
The National Party leader has had a rocky first eight months in the job, struggling in the preferred Prime Minister polls and having to deal with constant questions about his support amongst the caucus.
Many of these questions have come from The AM Show host Duncan Garner. On Monday he told Mr Bridges he could end the speculation by holding a vote.
There's no need to do something as silly and pointless as that.
"Why would I do that?" replied Mr Bridges, who had 7 percent support in the latest Colmar-Brunton poll - 2 percent ahead of his housing spokesperson, Judith Collins.
"I know I've got 55 MPs resolutely behind me."
Mr Bridges actually has 54 MPs behind him now, with the recent departure of Jami-Lee Ross.
"They know that under me, that in what has been a tough time, we have an underlying resilience," Mr Bridges continued. "We're back now focusing on what matters. I suspect our support to go even higher because the reality is when you've got an economy in drift, when you've got cost of living rising faster than wages - New Zealanders know they need us."
According to the Reserve Bank, the cost of living - as measured by the Consumer Price Index - rose 1.9 percent in the year to September, while media weekly incomes from wages and salaries in the year to June rose 4 percent, according to Statistics NZ.
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Pressed on why he wouldn't hold a vote to affirm his leadership, Mr Bridges told Garner he was "obsessed".
"There's no need to do something as silly and pointless as that."
National remains the biggest party in Parliament, with 55 MPs to Labour's 46. It was until recently the highest-polling party too, but fell behind Labour in the latest Colmar-Brunton poll, though the difference between the two is within the margin of error.
Prime Minister Jacinda Ardern polled at 42 percent for preferred Prime Minster.
Watch the full interview with Simon Bridges above.
The AM Show with Duncan Garner, Amanda Gillies and Mark Richardson, weekdays 6-9am on RadioLIVE and streaming live to the rova app on Android and iPhone.