The McEwen electorate, which takes in most of the Macedon Ranges, has the second-highest number of voters in the state. Lalor is the highest with 116,317 enrolled voters.

Labor's Rob Mitchell is contesting the seat for the second time after narrowly losing to incumbent Fran Bailey in 2007.

Ms Bailey has announced she will retire at the next election.

Kinglake police officer Cameron Caine has been endorsed as the Liberal Party's candidate for the seat of McEwen. He has been granted leave from his job and has ramped up his campaign.

Greens candidate Steve Meacher has previously contested the seat.

Family First has nominated Nillumbik councillor Belinda Clarkson, who is making her first bid for the seat.

Mr Mitchell admitted it would be another close contest.

"It's going to be very tight. It's always been a Liberal-held seat."

Ms Bailey raised allegations of vote-rigging after losing by seven votes to Mr Mitchell at the 2007 election.

She was declared elected after a recount of votes.