MCMAHON MP Chris Bowen will continue as acting Labor leader until either Bill Shorten or Anthony Albanese fills the position next month.
Labor members across Australia will vote in the leadership ballot, which will be balanced with a poll of federal caucus members on October 10.
The final result will be announced on October 13 at which time Mr Bowen will return as treasurer.
"It's a great honour to lead the Labor party even if it's only temporary," he said.
"I took the decision not to run for the position and under Labor rules it then falls to me as the next most senior member of the caucus who's not a ballot candidate.
"I see the role as leading the party while they go through the very important election of the new leader, which is a great process giving every party member a say, and holding the new government to account."
Mr Bowen has already voiced his concern over the gender imbalance in the Liberal party, with foreign affairs minister Julie Bishop as the only woman in federal cabinet.
"I think the fact that the Liberal party could only find one woman for the cabinet when we had six in the outgoing cabinet is a pretty sad indictment," Mr Bowen said.
He also criticised the Liberal party's boat people plan.
"They promised to stop the boats but so far all they've done is stop the press releases by not releasing the information every time a boat arrives," he said.
"If we tried that, the Liberal party would have rightly jumped up and down."