At least two potential challengers – Grant Schultz and Adam Straney – were contacted by a senior NSW Liberal on Tuesday and told the Prime Minister did not want Mrs Sudmalis to lose her endorsement. At least one was contacted directly by a senior Liberal from Canberra.

The intervention comes despite public statements made by Mr Turnbull and Treasurer Scott Morrison, who last week said the preselection process in the NSW Liberal Party was a grassroots matter while enthusiastically supporting Mrs Sudmalis as their preferred candidate.

Local Liberals told Fairfax Media on Tuesday they feared the seat would now be handed to Labor’s Fiona Phillips because Mrs Sudmalis was so unpopular. The Gilmore MP holds the seat by a razor thin margin.

Two possible contenders, radio personality Adam Straney and Nowra lawyer Paul Ell, haver decided against mounting challenges. Mr Schultz’s intentions remain unclear.

A source said Mr Ell was seriously considering mounting a challenge after being approached by party members who told him he would be the best candidate if the party wanted to retain the seat. He decided not to run after being told Mr Turnbull did not want Mrs Sudmalis challenged.

“The important thing now is for party members to support whoever the candidate is and that’s what I’ll be doing,” Mr Ell said.  

Nominations close at 5pm on Friday, May 25. The government is in a difficult position after the outcry over the dumping of assistant minister Jane Prentice in a Queensland preselection challenge.

While retaining Mrs Sudmalis might save the government some embarrassment in terms of gender politics, one senior local Liberal said if the seat was lost, the blame would fall on the Prime Minister.

Members face disciplinary action – including expulsion – if they speak publicly about internal party matters.