Liberal Party members on Sunday chose former federal Lower House MP Sarah Henderson ahead of Mr Mirabella in a preselection contest at Melbourne's Caulfield racecourse.

After other contenders were eliminated, Ms Henderson won a final vote 234 to 197 over Mr Mirabella.

"Obviously I'm disappointed," Mr Mirabella told The Border Mail.

"But I'm more disappointed for country Victoria because that was the platform I ran on and I think it's really disappointing the Liberal Party doesn't have a senator north of Melbourne."

Ms Henderson represented the Geelong-based seat of Corangamite for the Liberal Party from 2013 until this year's election when she lost it to the Labor Party.

Mr Mirabella had been encouraged to enter the contest after senior Liberals painted it as an opportunity for a country senator to take the place of the departing former minister Mitch Fifield.

However, Mr Mirabella said the higher number of delegates from Melbourne seats made his task tough.

"I made no bones about it I was standing as someone from rural Victoria and that's the problem you've got to overcome," he said.

Mr Mirabella, was seen as having the backing of conservative voters while Ms Henderson was considered more appealing to moderate Liberal members.

"The media framed it that way and there was some element of that, but the Prime Minister, Treasurer and half a dozen ministers were personally canvassing for Sarah Henderson, so it's pretty hard when you've got that happening," he said.

Prime Minister Scott Morrison had written a letter of support for Ms Henderson to preselectors, highlighting her dogged campaign at May's federal election.

After her success on Sunday, Ms Henderson said she was "incredibly proud and honoured" to be chosen to become a senator.

"I will be working around-the-clock, right across this great state, representing the people of Victoria," Ms Henderson said.

The Liberal Party's last candidate for Indi Steve Martin congratulated Ms Henderson and offered commiserations to Mr Mirabella.

"Obviously Greg has a connection to Indi but Sarah has also held a regional Victorian seat and I expect her to advocate for regional Victoria," said Mr Martin, who was not among the six Indi delegates to vote in the preselection.

Mr Mirabella, who is married to former Indi MP Sophie Mirabella, would not rule out seeking a parliamentary role in the future.

"It's a possibility but it's not something I'm going to think about," he said.

"I'm going to take some time off (politics) and get back to the rest of my life."

The Senate vacancy was created through Mr Fifield being appointed ambassador to the United Nations in New York.