Prime Minister Malcolm Turnbull has paid tribute to veteran Liberal MP Bronwyn Bishop, whose parliamentary career is all but over after she lost preselection in her Sydney seat of Mackellar.

Former Liberal staffer Jason Falinski defeated Ms Bishop 51 to 39 in a meeting lasting five-and-a-half hours on Saturday evening, however the result will still need to be formally endorsed by the Liberal Party executive.

Mrs Bishop, who has held the seat on Sydney's northern beaches for 22 years, left Saturday night's meeting with a group of supporters.

"It's been an honour to serve the people of Mackellar," she told reporters on her way out.

Mr Turnbull said it was a disappointing result for Mrs Bishop but thanked her for her "enormous" and "indelible" contribution to Australian public life.

"She's been a magnificent figure on the national stage as a minister, as a member, senator, speaker," he said.

"Bronwyn is unforgettable; she's dynamic, she's colourful, she's charismatic and we thank her, on behalf of the Liberal Party, we thank her for her extraordinary service."

Earlier, former Prime Minister Tony Abbott described Mrs Bishop as a "warrior for good causes" and said she deserved the gratitude of all members of the Liberal Party.

Before Saturday's ballot some party elders publicly criticised Mrs Bishop's decision to recontest the seat, arguing it was time for the 73-year-old to retire and allow new blood into the ranks.

Mr Falinski praised the outgoing MP for her "long service and dedication to the Liberal cause" and said it was an honour to have been selected.

"I want to thank the Liberal Party for bestowing this honour on me," he said as he left the meeting.

"It is a privilege to be given their faith to represent the Liberal Party on the northern beaches. There's no other seat that I've ever wanted to represent in the federal parliament than Mackellar."

Mr Falinski, a moderate, and hard-right candidate Walter Villatora were widely seen as the biggest threats to Ms Bishop.

Mr Villatora was this week publicly endorsed by Mr Abbott, who once described himself as the "political lovechild" of Ms Bishop and John Howard.