Internal brawling dividing the Victorian Liberals over blue-ribbon seats has escalated as supporters of federal MPs threaten to trigger a showdown so they can overturn a decision to open up preselections early next year.

Concerns are mounting among the MPs' supporters, who argue early preselections could turn sitting members into disempowered "lame ducks" if they lost the right to fight for re-election while still needing to serve out more than two years of their term.

But the push to delay the preselection timetable has prompted accusations from the state branch that MPs are putting “factional shenanigans” above the party’s interests.

Preselections for the state’s seats are scheduled to begin in January.