Shellshocked Liberal MPs will meet at 3pm on Thursday to elect a replacement for Barry O'Farrell as leader following his dramatic resignation as NSW Premier.

On Wednesday night party sources described the ballot as a likely contest between Treasurer Mike Baird and transport minister Gladys Berejiklian. However, finance minister Andrew Constance was reportedly also working the phones seeking support.

Ms Berejiklian has yet to confirm to colleagues that she will run.

One party source suggested Ms Berejiklian, the member for Willoughby, may be reluctant to run for fear of opposition from the Liberal party's right faction.

"She's a warrior of the left," the source said. "She knows if she becomes Premier the right will try to tear her down".

But another party source dismissed this view, arguing that "the numbers are all over the place".

"The issue is what will provide stability for the government," the source said. "This is not just factional. Everyone's going to be looking at what's best for the state".

A source from the right faction insisted its members were "watching and waiting" before deciding who they would back.

Mr Baird, the member for Manly, enjoys support from the party's right faction due to his conservative social politics.

Mr Baird is also regarded as a strong advocate of the sale of the electricity poles and wires, which Mr O'Farrell as Premier has been reluctant to embrace without an electoral mandate.

However, suggests have emerged Mr Baird could be hampered by his relationship with Nick Di Girolamo, the Liberal identity whose gift of a $3,000 bottle of Grange Hermitage to Premier Barry O'Farrell led to his resignation.

Mr Baird was a shareholding minister when Mr Di Girolamo was appointed a director of the State Water Corporation in June 2012. He has previously been pursued by the opposition and the Greens over the appointment, which he has insisted was a decision of the cabinet.

Ms Berejiklian has long been regarded as Mr O'Farrell's favoured successor. He appointed her as the party's campaign spokesman during the 2011 election campaign and rewarded her with the key transport portfolio upon coming to government.

If she declines to challenge for the leadership there is speculation she could be made Treasurer.

The new Premier will be under pressure to carry out a comprehensive cabinet reshuffle.

There is speculation casualties could include planning minister Brad Hazzard - one of Mr O'Farrell's closest confidantes whose clashes with independent MPs in the upper house saw he overhaul of the planning act blocked.

Other ministers potentially in the firing line are attorney-general Greg Smith health minister Jillian Skinner and environment minister Robyn Parker.

What happens now

- Liberal MPs to meet on Thursday to elect a new leader and Premier.

- Treasurer Mike Baird and transport minister Gladys Berejiklian being urged to run.

- Major cabinet reshuffle expected soon after.