Labor leader Anthony Albanese has again been forced to defend his position after copping more friendly fire.
Bill Shorten took a thinly-veiled swipe at his successor on Sunday for adopting a "tiny" policy agenda in opposition.
Launching a collection of essay by members of the Labor Right faction, Mr Shorten argued the party must "stand for something" if it wanted to win.
Mr Albanese denied he was frustrated by the speech and said he would take a "good Labor agenda" to the next election.
"Bill Shorten launched a book. Labor Party people write books. Labor Party people launch books. We're the party of ideas," he told reporters in Canberra on Monday.
Labor MP Joel Fitzgibbon, who quit the frontbench in November, has spent months arguing the party is drifting too far to the left and losing touch with its traditional base.
He told Sky News Mr Shorten had learnt his lesson after Labor's shock 2019 election loss.
"He was encouraged in the interest of collective unity to be taken to policy positions, very progressive positions both on climate change and on wealth redistribution, which did him and the party significant harm," Mr Fitzgibbon said.
"He's expressing frustration that we're not now doing better."
Mr Fitzgibbon denied the former leader's speech would inflame divisions within the party.
"I hope it drives us toward a point of unity and agreement on the things that will matter so much when the next election comes around," he said.
"I welcome more people speaking out about some of the challenges we face, in particular the need to put labour back into the Labor Party and get back to our traditional base."
Australian Associated Press