Bill Shorten has told Labor supporters "the fight goes on" after the election loss, as Anthony Albanese looks set to replace him as leader.
Factions are also meeting to decide Mr Albanese's deputy and shadow cabinet.
Mr Shorten has stayed mainly quiet since Saturday's shock loss but he sent a note to Labor supporters on Friday afternoon thanking them for their support.
"We're all hurting right now," Mr Shorten said in his email.
"For me, the greatest disappointment is all the things a good, strong, reforming Labor government could have done for our country and for the millions of our fellow Australians who voted for us."
Mr Shorten said after the "hard, raw" moments on Saturday, Labor was resilient.
"The fight goes on - and Labor still needs you in the fight with us. I urge you to keep the faith, to unite behind our new leadership," he said.
Queensland Labor MP Jim Chalmers withdrew from the leadership race on Thursday, leaving Mr Albanese so far unopposed for the top job.
Mr Chalmers won't contest the deputy role either.
Mr Albanese is confident but not complacent about becoming leader, when nominations close on Monday morning, and is promising to be tough on the government when parliament returns.
"They haven't got a blank cheque, they need to be held to account by a strong opposition," he told Nine's Today program on Friday.
"And we also need to be resetting our policy framework over the next three years."
Victorian Labor right-faction MPs Richard Marles and Clare O'Neil are both considering a run for deputy.
Labor frontbencher Tony Burke says Mr Marles has been ringing colleagues about the role for "quite some time".
Labor has aimed to have a man and a woman in the leadership duo, from different states and factions.
Labor equality group EMILY's List called for women to be included in the two lower house and two upper house leadership positions.
If there are no further nominations for leader, the Labor caucus is expected to meet as early as Wednesday to confirm its leadership team, including deputy leader and senior Senate personnel.
Penny Wong is expected to remain Labor's senate leader.
The Victorian Right spent Friday trying to figure out who to support for the deputy leadership.
Queensland Labor MP Shayne Neumann pre-emptively argued for a spot in the new shadow cabinet, warning the party it needs a strong voice in Queensland.
Victorian Left factional powerbroker Kim Carr announced he would not expect a shadow ministry role.