Federal Liberal MP Ann Sudmalis will not contest the next election after last ditch pleas by Prime Minister Scott Morrison for her to stay on, failed.
Ms Sudmalis, who holds the southern NSW coastal seat of Gilmore by just 0.7 per cent, has told The Australian Financial Review that she informed Mr Morrison at a meeting on Monday that she was withdrawing her nomination for preselection.
She did so after she lost control of her local federal electoral conference (FEC) when it was stacked by forces aligned to local state Liberal MP Gareth Ward.
While Ms Sudmalis believed she was still likely to win her preselection against challenger Grant Schultz, she said she would have been unable to work with the people stacked into her FEC, many of whom had no campaign experience.
"I can't work with the team there anymore, they don't know the electorate well, they don't know how to campaign."
"This is absolutely not about Scott, he's a very dear friend and he's a very good man," she said.
"I believe he can bring our party together, he's a visionary, Scott is the man who can pull this country forward."
Her departure, however, is a headache for the struggling government.
Already, Victorian marginal seat holderJulia Banks has announced she is quitting at the election in protest over the leadership events of last month and, for the same reason, Craig Laundy is expected not to run in his marginal western Sydney seat of Reid.
With Ms Sudmalis also going, combined with the net effect of recent electoral redistributions, the Coalition could begin the next election campaign with a notional 72 seats out of 151.
That will drop to 71 if the Coalition loses the October byelection for Mr Turnbull's seat of Wentworth.
Ms Sudmalis said she sent Mr Morrison a letter last week informing him she wanted to withdraw her nomination for preselection. He refused to open it as he tried to talk her around.
On Sunday, the same day Mr Morrison dismissed reports surrounding Ms Sudmalis as "media speculation", he opened the letter. At about 9am Monday, he met Ms Sudmalis but she would not change her mind.
"It's difficult for Scott,” Ms Sudmalis said.
"Last week he did not want to open that letter. It stayed unopened until yesterday afternoon.
"When he did open it, he was pretty disappointed. We are mates."
Ms Sudmalis said her resignation had been a long time coming. In the 5½ years she had held the seat, she had been undermined at a local level.
"It's been a slow, steady, agonising and annoying process," she said.
Asked about Ms Sudmalis's resignation, frontbencher Christopher Pyne said politics was "not a life sentence" and described resigning as quite "a nice way to go".