Professor Warhurst said it would be an ''invidious position'' for anyone selected to fill Mr Stefaniak's spot on the Liberal ballot so late in the election campaign.

''Unless you were a truly outstanding candidate, you would almost certainly be making up the numbers,'' Professor Warhurst said.

''Candidates have been out campaigning for months now, but it would be a very, very difficult task for anyone coming in.''

Radio personality Mark Parton has previously been touted as a celebrity candidate for the Liberals.

But yesterday Mr Parton said he had not been approached to stand in Mr Stefaniak's spot.

Professor Warhurst predicted Labor and the minor parties could also pick up some spill-over votes in the upcoming election from Mr Stefaniak's withdrawal.

''For those voters who are inclined to vote for those they know,'' Professor Warhurst said.

''And there are always a few of those the beneficiary may be Mr Stanhope himself.

''Labor certainly would be one of the beneficiaries and Vicki Dunne perhaps as the remaining sitting Liberal.

''It makes it almost certain that one of those new Liberal candidates will come in.''

Liberal MLAs have been quiet on Mr Stefaniak's decision to leave politics for an appointment on the Government's new super-tribunal.

And the cross-bench was not much kinder.

Greens MLA Deb Foskey, who is retiring at the election, said it was probably a good decision for Mr Stefaniak to leave politics.

Canberra Party and former Liberal MLA Richard Mulcahy claimed the move showed deep divisions in the Liberal party.

Mr Stefaniak was not available for comment yesterday.

The Liberals are expected to hold a party meeting later this week to fill Mr Stefaniak's spot on the ballot.

Party director Andrew Heath refused to comment on Mr Stefaniak's departure.

Mr Heath said the party would make a decision on the matter in due course.