Tony Burke, a cabinet minister in the Rudd and Gillard governments, is declaring his support within the party for Mr Albanese and is leading a revolt within the NSW right faction to get behind the left-winger instead of the right's own Chris Bowen.

It is understood finance spokesman Jim Chalmers, who was openly canvassing support for the top job, will fall in line behind Mr Bowen to avoid further splitting the right-wing vote.

Mr Shorten strongly backed his deputy leader, Tanya Plibersek, when she was weighing a tilt at the leadership on Sunday - until she pulled out on Monday citing family reasons. He has since joined a factional phone hook-up to discuss potential replacements and lobbied MPs in Victoria and interstate.

The activities of Mr Shorten - who beat Mr Albanese for the leadership in 2013 - have shocked some colleagues who say he is "up to his neck in it" and should stay out of the selection process.

"He was initially ringing people around the country urging them to vote for Tanya. He has also been actively lobbying people making sure someone runs against Albo," said one senior MP.

"It's weird. As a former leader you have an opportunity to be above it. You get treated with a whole respect for making that choice."

Those close to Mr Shorten argue he should play a role in preserving the unity he fostered during his long tenure as opposition leader. "Bill's focus is entirely on keeping the party as united as it's been for the past six years," one source said.

Mr Bowen declared his hand on Tuesday promising to "lead the economic debate, which we must win". However, many in Labor believe Mr Bowen's close proximity to the party's failed economic agenda is exactly what disqualifies him from the top job.

Privately, some senior figures said they were "gobsmacked" he threw his hat in the ring.

Mr Albanese will benefit from a split in the party's right faction in NSW which is expected to result in about half its MPs abandoning Mr Bowen for the left-winger, including Mr Burke.

Mr Burke is not a leadership contender but would stand for the deputy's position in the unlikely event the party does not conclude the job should go to a woman. All the declared candidates and possible challengers for the leader's job are men.

Clare O'Neil, a right faction frontbencher from Victoria, would be a prime candidate for the deputy leadership in the event Mr Albanese becomes leader, while Mr Bowen identified Linda Burney and Mark Butler as potential deputies.

While Mr Bowen spoke of economic growth as "the best poverty alleviation program ever invented," Mr Albanese cast himself as a social democrat keen to drive economic growth but one who would not be shy about government intervention in the economy.

He said there was not a massive ideological chasm between himself and Mr Bowen but added: "I believe in markets but I believe that there's a government role to intervene in a market economy because markets don't have a conscience.

"Markets are very good at a range of things in our economy. What they do often, though, is entrench existing economic and social relationships in terms of power structures.

"We seek government so that we can intervene to change outcomes. It's not to change who's in the white [Commonwealth] cars. There would be a strong agenda were I to lead the Labor Party but it would also be one that's founded upon a consensus model."

Mr Albanese's bid will also be bolstered by a split among the right-wing unions. The Transport Workers Union and others are expected to offer soft support for Mr Albanese or at least avoid campaigning for Mr Bowen.

Many of Mr Albanese's backers in the NSW Right are those who were ready to install him as Labor leader last year if Bill Shorten faltered badly in the July "Super Saturday" byelections. However, the party retained all its seats and Mr Shorten's leadership survived.

Others in the faction who are friends with Mr Bowen are expected to support him, such as Jason Clare and Ed Husic - the three men shared a house in Canberra during sitting weeks.

Announcing his bid for the leadership while standing outside his childhood home in the western Sydney suburb of Smithfield, Mr Bowen acknowledged he was not the favourite against Mr Albanese. But he said Saturday's unexpected election result meant he was "a bit over favourites".

with Samantha Hutchinson and Kylar Loussikian

- SMH/The Age