By chief political correspondent Simon Cullen

Video: Kevin Rudd backs China's health and ALP chances

Related Story: Rudd 'won't be silenced' ahead of election

Kevin Rudd's first major interview since losing February's leadership challenge has sparked renewed discussion among Labor MPs about his ambitions.

In an interview given to the ABC's 7.30 as Prime Minister Julia Gillard took time out to mourn her father's death, Mr Rudd said he "won't be silenced" when it comes to pushing Labor's agenda.

"I'm out there arguing the Labor case. I'll do it anywhere and everywhere that I can," he told 7.30 from the World Economic Forum in China.

One of Mr Rudd's strongest supporters, Labor Senator Doug Cameron, said it was "fantastic" to have the former prime minister campaigning so publicly against the Coalition.

"I think he's one of the best politicians we have and he should be out there," Senator Cameron told reporters in Canberra.

"He's one of the most popular - if not the most popular - politician in the country, so it's great that he's out there, it's great that he continues to play a team game, and it's great that he's sending a Labor message.

"We're in the fight of our lives as the Labor Party.

"I was in the polling booths at the... local council elections (in New South Wales), and it really is a problem for Labor when you've got blue collar workers with the arse out of their pants taking Liberal how-to-vote cards and voting Liberal."

Those pushing for a return of Mr Rudd to the prime ministership have told the ABC that anything he does will be viewed in the context of the leadership, but argue that he has been angered by the savage public service budget cuts in his home state of Queensland.

He's one of the most popular - if not the most popular - politician in the country, so it's great that he's out there, it's great that he continues to play a team game, and it's great that he's sending a Labor message.

Labor Senator Doug Cameron

On 7:30, Mr Rudd said Queensland Premier Campbell Newman had no mandate to sack thousands of public servants, and warned it was just a precursor to what a federal Coalition government under Tony Abbott would do.

"Remember what we've had with Queensland slashing health, New South Wales slashing education not to mention the boost in TAFE fees," he said.

"This frankly is just the entrée, the main course lies with Mr Abbott.

"That's why I've got a responsibility, like all members of the parliamentary party, to get out there [and] put my best foot forward to argue the case."

Mr Rudd spectacularly lost a leadership ballot to Ms Gillard in February, and declared at the time that he would not launch a second challenge against her.

But many Labor MPs believe he still harbours strong leadership ambitions and would be prepared to return to the top job.

Asked last night whether he believed Labor could win the next election under Ms Gillard's leadership, Mr Rudd had to be pushed by host Leigh Sales to mention the Prime Minister's name.

Kevin Rudd: "Of course the Government can prevail against Mr Abbott at the next election."

Leigh Sales: "With Julia Gillard as the leader?"

Rudd: "Under the prime minister's leadership to do so."

Saes: "Under this prime minister's leadership?"

Rudd: "Under the prime minister's leadership to do so."

Sales: "Under Prime Minister Julia Gillard?"

Rudd: "I just said that. Under Prime Minister Gillard's leadership."

Labor frontbencher Tony Burke has described the exchange as a "human reaction" given the history between the pair, and he did not think Mr Rudd was actively campaigning for the leadership.

Mr Burke was one of a number of Cabinet ministers who declared earlier this year that they would not serve under Mr Rudd if he was again made prime minister.

"I made some very strong comments earlier in the year," Mr Burke told ABC Newsradio.

"I don't resile from what I said, but I don't see any point in continuing to trawl over that."

Labor Senator Stephen Conroy, who previously described Mr Rudd as a "'complete and utter fraud", this morning said the former prime minister was simply campaigning against the Opposition.

"Kevin Rudd is campaigning against Campbell Newman's savage cuts to the health and education sectors in Queensland," he told Channel Nine.

"It is very important for every member of the Labor Party to point out where there's been broken promises by Campbell Newman and by Barry O'Farrell."

Colleagues welcome Rudd's return to limelight - ABC News (Australian Broadcasting Corporation)