Prime minister Tony Abbott’s leadership of the Liberal Party is now terminal, former Victorian premier Jeff Kennett says.

Kennett says the Abbott government should bring on a spill of leadership positions or risk derailing next month’s NSW state election in a similar way to Queensland.

“I think sadly the realisation has dawned on most politicians that the leadership of the party is now terminal,” Kennett told ABC Radio on Wednesday.

“It needs to be resolved as quickly as possible so that the party can move on.”

Kennett said the government’s woes were self-inflicted and he would not be drawn on who should lead the party to the next election.

“I’m not going to give the kiss of death to any one candidate or two,” he said.

Federal Education minister Chris Pyne said he had always been a great fan of Kennett’s but the former premier had never been a member of federal parliament and was defeated in the Victorian election.

“Jeffrey is not the oracle of all wisdom when it comes to politics,” he told ABC Radio.

Pyne said Kennett was very fond of giving his views now he was in retirement, but they weren’t always helpful.

“We have a leader and his name is Tony Abbott,” Pyne said.

“He has done a very good job and the party is sticking with him.”

Abbott today dismissed backbench calls for a leadership spill as a sign of a “robust” Liberal party room.

The prime minister could face a challenge as early as next week after three of his MPs publicly broke ranks to disavow their leader.

West Australian backbencher Dennis Jensen has told Abbott he no longer has his support while Queenslanders Warren Entsch and Mal Brough say they want the leadership issue resolved.

Abbott said he understood why some MPs were nervous in the wake of the Queensland election, but warned them against repeating the turmoil of previous Labor governments.

“We’ve always had a robust party room, and I hope that will always continue,” he told Macquarie Radio on Wednesday.