Nominations for the leadership will open on Wednesday at 2pm and will close on Friday afternoon, returning officer Daniel Mookhey said in a statement on Tuesday.

If more than two candidates come forward a ballot will be held for both the rank and file members and the parliamentary party.

That process will take "a number of weeks" to give all members a chance to vote.

Interim leader Penny Sharpe has held the top job since former leader Michael Daley stepped down following a resounding defeat in the March 23 state election.

Shadow treasurer Ryan Park has led the party in the Legislative Assembly since April.

NSW Labor held off selecting a new leader until after the federal election in order to prevent a potentially costly distraction to Bill Shorten's national campaign.

But Mr Shorten's defeat at the weekend has now triggered his resignation as well.

That means both NSW and federal Labor will be working to install new leaders at the same time.

Mr Daley had just four months to turn the state party's fortunes around after his predecessor, Luke Foley, resigned in disgrace.

But his campaign was derailed when a video emerged of him telling a pub forum that Asian migrants were taking local jobs and he later stumbled on key numbers behind his education policies during a live television debate.

Mr Daley and Ms Sharpe won't contest the leadership but Chris Minns - who unsuccessfully ran against Mr Daley in November 2018 - is expected to put his hand up again.

Frontbenchers Jodi McKay and Kate Washington are also considering entering the race.

"Labor will give our members a direct say over who should be leader," Ms Sharpe said in a statement on Tuesday.

"We are proud that we are the most democratic party in the NSW parliament."

Australian Associated Press