The Liberal Party may attempt to knock off Geoff Shaw in the seat of Frankston at the state election, paving the way for unwanted tensions between the balance-of-power MP and the Napthine Government.

The Sunday Age understands that Sean Armistead, who ran as the Liberal candidate in the seat of Melbourne at last year's federal poll, will nominate for preselection later this month. Frankston mayor Darrel Taylor is also believed to be eyeing off the marginal electorate.

The move is likely to prove tricky for the government, which relies on the independent MP to pass legislation. Adding to the precarious situation is the fact that Mr Shaw no longer has confidence in Liberal speaker Ken Smith, which could again make parliament unworkable when it resumes in February, unless the Coalition can rein him in.

Mr Shaw did not respond to calls or emails in time for deadline, and it is still not known if or how he plans to contest the November 29 poll. Still a rank-and-file member of the Liberal party, the unpredictable MP has not ruled out trying to return to the parliamentary team – a move the premier says is highly unlikely – or even quitting politics altogether. He also met with Clive Palmer last year, but did not reveal whether the billionaire businessman asked him to join his Palmer United Party.

Liberal sources say Mr Armistead would be a strong contender for Frankston, because he grew up in the area, his family still lives there, and he has growing support, particularly within the Frankston branch. He is also well regarded by party chiefs for running a solid federal election campaign in the Greens seat of Melbourne, where he achieved about 23 per cent of first-preference votes.

Frankston is now notionally held with a slender margin of 0.6 per cent following a redrawing of electoral boundaries.