Victoria could have a new opposition leader within days as former Liberal leader Matthew Guy seeks the support of colleagues to topple leader Michael O’Brien in a party room coup his supporters are proposing to call as early as Tuesday.

Mr Guy has been considering a return to the leadership for a number of months but has consistently and publicly denied he would seek the job he held between 2014 and 2018, culminating in a devastating election defeat to Premier Daniel Andrews.

Four Liberal Party sources, speaking anonymously to reveal internal party affairs, said the former leader had begun calling Liberal MPs on Sunday to seek their support to win back the leadership of the ailing state party. Sunday was the first time Mr Guy has told colleagues outside his inner circle that he intends to run.

Mr O’Brien fended off a leadership challenge from backbencher Brad Battin earlier this year after Mr Guy and his supporters voted against the rebel group. However, since that challenge, followers of Mr Guy and Mr Battin have put behind them a period of personal animosity in the attempt to improve the Coalition’s political prospects by removing Mr O’Brien.

Parliament is set to sit this week after a weeks-long break. However, it is not clear whether a full party room meeting will be able to be held due to density limits. Opposition MPs have sought advice from Parliament’s presiding officers to determine whether the full party room of 31 MPs can meet in the same room on Tuesday.

If the party room meeting cannot be held, party sources say Mr Guy’s supporters are determined to find any way to conduct the leadership spill. The state election is due to be held in November next year.

The party is effectively split into three groups. One coalesces around Mr O’Brien and includes key backers Kim Wells and Gary Blackwood. The second includes Tim Smith and James Newbury, who support Mr Guy’s return. The third group, which brought on the March coup attempt, is led by Ryan Smith, Richard Riordan and Brad Battin.

The latter two groupings have managed over winter to reconcile strong personal differences and the leadership team of a potential Guy-led opposition will include members of the Battin group.

The imminent challenge comes after a heated party meeting last week when Liberal MPs aired anger at being excluded from decision-making over the party’s policies.