Finance Minister Bill English has the numbers to become the new National Party leader and with it New Zealand's next Prime Minister.
At least 30 National MPs have publicly confirmed they will back him in the leadership contest.
The confirmation of the support comes after Judith Collins pulled out of the leadership race and declared her backing for Mr English.
Jonathan Coleman, the remaining rival to Mr English, told reporters after question time this afternoon that he hadn't yet decided his next move.
There had been rumours he was going to withdraw from the race.
Corrections and police boss Ms Collins threw her name in the ring on Monday, having been booted from cabinet in 2014 before being reinstated last year.
She is latest high profile National MP to back Mr English, including Mr Key.
Earlier, Justice Minister Amy Adams confirmed to 1 NEWS that she will not be seeking the deputy leader position of the National Party.
Ms Adams, who had been seen as a potential contender, was undecided yesterday about whether she would join the race.
However, she says she has now decided to end the speculation and is confirming she will not be seeking the deputy role.
She says she will be backing Bill English for leader and Paula Bennett as his deputy.