Kevin Rudd was impossible as a boss, according to Attorney General Nicola Roxon, who served as head of the Health Ministry until the former prime minister was booted out in a party coup in 2010.

Ms Roxon described Mr Rudd's governance as 'ludicrous' and as head of the Australian Labor Party he seemed more dispensed on administering based on his whims, with the advises offered by cabinet members rarely listened to.

The attorney general recalled that Mr Rudd had once planned to submit his health reform plans before a national referendum, which would have empowered the federal government to assume responsibility of the Australian health care system.

Ms Roxon said she advised Mr Rudd against the plan, arguing that historically Australian states were not inclined to surrender their health care programs to the national government.

"We wouldn't win the referendum. Look at the history of referendums. The states do not agree with us ... the campaign would be very heavily opposed to us," Ms Roxon was reported by the Australian Associated Press (AAP) as saying in going against Mr Rudd.

Nonetheless, Mr Rudd insisted that the initiative made sense and he would have squeezed that referendum with the 2010 general elections but he was ousted months before election day.

There were many instances that Mr Rudd kept his cabinet clueless on the general path of his government, according to Ms Roxon.

She added that there were times the resigned Foreign Minister would keep her out of the loop on official health tours.

"We couldn't get confirmation from the prime minister which hospital or which city he was going to be in," Ms Roxon told Sky News on Friday.

Ms Roxon also dismissed Mr Rudd's claim that the government health reform programme, under her stewardship, was railroaded with the blessings of Prime Minister Julia Gillard.

"We went through a very detailed health reform process with Kevin as prime minister and we were able to progress an enormous amount of things that he should be proud of and I am proud of as well," Ms Roxon said.

While she noted that Mr Rudd would most likely exclude her from his government, Ms Roxon said that serving under a Rudd government is not a prospect she looks forward to.

Mr Rudd returned from Washington on Friday and is reportedly mustering support for the Labor leadership showdown that Ms Gillard had called for Monday next week.

"If Kevin succeeds I won't want to serve in his ministry but I will absolutely wish him and the government the best of luck," Ms Roxon stressed.

She added that she will campaign of course for Labor and in the event Mr Rudd returns to his old post, Ms Roxon could only hope that the former prime minister is a changed man, as he now regularly claims.

Ms Roxon belongs to a group of senior Labor ministers who had stepped up their efforts to shore up the chances of Ms Gillard retaining the ALP leadership and the prime minister seat by launching spirited attacks against Mr Rudd, according to media reports.

While Mr Rudd has yet to formally announce that he will contest the Labor leadership, his words hint of such possibility while his supporters were reportedly working behind the scene to convince Labor caucus members to back his candidacy.

According to Agence France Presse (AFP), Mr Rudd banks on his popularity, a factor that could convince Labor members to dump Ms Gillard and propel him to the top post anew.

"The core question for members of the Australian parliamentary Labor party, for the Australian people, right now is whether they believe the current prime minister has the trust and confidence of the Australian people," Mr Rudd was quoted by AFP as saying upon his return.

Ms Gillard, however, remains confident that she is the best Labor candidate to thwart efforts by Opposition Leader Tony Abbott to win government power despite recent surveys showing that Labor will be easily defeated by the Coalition.