Despite more than two years until the next poll, opposition leader Matthew Guy wants preselections in Liberal-held seats to be finalised by the end of the year, putting the spotlight on the future of several senior backbenchers and opening the door to a series of hotly contested battles in their prized electorates.

Jockeying behind the scenes has already begun in seats where Liberals are expected to retire or may be considering it, including the safe seat of Brighton (held by former deputy leader Louise Asher with a margin of 9.77 per cent); Nepean (held by former education minister Martin Dixon with a 7.63 per cent margin) and Evelyn (held by former speaker Christine Fyffe, with a buffer of 9.59 per cent).

But with the proportion of Liberal women at the federal level woefully low, the party will be forced to somehow significantly boost its number of female candidates at the state level if Mr Guy is to have any chance of delivering on his own gender-based targets.

Under those targets – announced at a Liberal state council meeting in April – the proportion of female MPs in the parliamentary team would increase by 10 per cent at every election, rising from 27 per cent this year, to 37 per cent at the 2018 poll and almost half by 2022.

While insiders concede the goal is highly ambitious, Mr Guy has repeatedly told his party that if it wants to represent a "contemporary Victoria" it needed to be more diverse – with greater gender representation, young blood and more candidates from multicultural backgrounds.

However, despite his push to regenerate, Mr Guy said it would be up to party members to determine who their local candidate was.

"I've been very clear about that – there won't be any top-down enforcement about who should be where. Party members determine preselections and I'll leave it to them to make what they believe is the right decision for each electorate," he told Fairfax Media.

Liberal preselections are expected to open in coming months – well before ALP preselections are due to start early next year.

In Nepean, Mr Dixon, who has been in Parliament since 1996, is expected to make an announcement about his future within weeks. Candidate hopefuls for the Mornington Peninsula-based electorate are likely to include former Prahran MP Clem Newton Brown – who lost his seat to the Greens at the 2014 election – and former Liberal candidate for the seat of Frankston, Sean Armistead.

In Brighton, sitting MP Ms Asher has not publicly declared whether she plans to recontest, but it is widely anticipated that she will step down after almost 26 years in politics. Potential candidates include Bayside councillor Felicity Frederico, public affairs manager James Newbury and upper house MP Margaret Fitzherbert.

Ms Fyffe could not be contacted in time for deadline. The outer suburban seat of Rowville was also being eyed off, as was the bayside seat of Sandringham, but it is understood that the sitting MPs (Kim Wells and Murray Thompson, respectively) plan to run again at the next poll.