Bronwyn Bishop's long and controversial political career is over after Liberal Party members voted to dump her from the safe Sydney seat she's held for more than two decades.

Businessman Jason Falinski will be the Liberal candidate for Mackellar at the upcoming federal election after 91 preselectors called time on Mrs Bishop's 29 years in Federal Parliament.

The result came after a gruelling five hour showdown between seven candidates at the Dee Why RSL on Sydney's northern beaches. There were four rounds of voting before Mr Falinksi triumphed.

He secured 51 votes to Mrs Bishop's 39. There was one informal vote.

"It has been an honour to serve the people of Mackellar," a smiling Mrs Bishop said as she left the venue.

The moderate Mr Falinski was Prime Minister Malcolm Turnbull's preferred candidate. He has also worked as an adviser to former Liberal leaders John Hewson and Barry O'Farrell.

He beat out the 73-year-old Mrs Bishop and former prime minister Tony Abbott's preferred candidate, Walter Villatora.

Mrs Bishop first entered the Senate in 1987 and switched to the lower house in a by-election in 1994. Once touted as a leadership contender, her star faded after she suffered a sizable swing against her.

She served as a minister for five years in the Howard government but was dumped in 2001. Mr Abbott restored her to the frontbench when he was opposition leader and made her Speaker when he won in 2013.

She was a divisive Speaker who was accused of blatant bias. She set a new record on the use of Standing Order 94a: of the 400 politicians she booted out of parliament in her roughly 18 months on the job, 393 of them were Labor MPs.

She was dumped from that prestigious position last year after it was revealed she had spent $5000 of taxpayers' cash chartering a chopper to travel the short distance from Melbourne to Geelong to attend a party fundraiser.

She surprised many when she decided to seek preselection again rather than retire. She said she wanted to stay in Parliament to represent the interests of seniors and keep Australia safe from Islamic State.

She will retire on a taxpayer-funded pension of $250,000 a year given her lengthy Parliamentary career and roles as a minister and Speaker. She will also get access to the Life Gold Pass for free travel.

Elsewhere on Saturday, Australian Catholic University director Julian Leeser was selected to replace Philip Ruddock as the Liberal candidate for the nearby safe Sydney seat of Berowra. The former solicitor and think tank director has also worked as an advisor to Mr Ruddock and Mr Abbott.

He won easily, with 97 of the 114 votes on offer.

Mr Ruddock announced his retirement earlier this year and the government appointed him a special envoy for human rights.

In Victoria, the Liberals selected former political advisor Duncan McGauchie to replace Sharman Stone in the regional seat of Murray. His main rival will be former AFL coach Damian Drum, who is running for the Nationals.

But now the Liberals have another preselection headache after veteran NSW MP Bob Baldwin announced his retirement from politics.

"I have not come to the decision lightly and I feel it is time to move on with my life and allow others the opportunity to fulfil their dreams of entering parliament with fresh enthusiasm," he said in a statement on Facebook. Mr Turnbull said the Parliament was losing one of its "true characters".

The Bishop preselection has become a source of tension between the Liberal Party factions, including the delicate alliance between the moderates - which includes Mr Falinski in its number - and the centre right which backed Mrs Bishop despite widespread calls for her to retire from outside and inside the Liberal Party.

Opposition Leader Bill Shorten said on Saturday the Liberal Party was "at war with itself".

With Heath Aston