Thumbs-up this time, or not? Kevin Rudd during question time in Parliament on Wednesday. Credit:Alex Ellinghausen ''I can't get into support or not supporting issues on the basis of someone else's future. That's not the right way to operate,'' he said. ''I don't think it's terribly under threat anyway.'' Mr Windsor did say, however, that division in Labor ranks was a ''one way street to oblivion'' for the government, and it would be in everyone's best interests for the leadership to be resolved as quickly as possible. As Ms Gillard enters what is potentially the most vulnerable day of her 2½-year leadership, she has been assured by backers inside the government and by key union supporters in the broader labour movement that her caucus majority is sound and will not crumble in the face of a challenge. Her supporters maintain that the Prime Minister is not for turning. ''Julia Gillard is as tough as they make them,'' declared Treasurer Wayne Swan. ''She's going to beat Tony Abbott because she's focused on the big reforms for the future.''

For his part, Mr Rudd has repeated his pledge not to make an attempt on the leadership, leaving only the option of a move by others or by Ms Gillard herself. In a development transparently calculated to increase the temperature of the burgeoning leadership crisis, the government's chief whip and key Rudd numbers man, Joel Fitzgibbon, on Wednesday used a Fairfax Media online interview to publicly stake out the battle-ground for any showdown, saying it would be ''silly to tell people … that there is nothing going on''. Mr Fitzgibbon said it would make no sense to change leaders after the May 14 federal budget. ''I think this idea that the party could change leaders between budget day and the September election is just a silly concept,'' he said. While Mr Fitzgibbon was careful not to openly endorse a change of leaders now, his comments were seen as a deliberate message to undecided MPs in the caucus that it is effectively now or never.

Fairfax Media was told that the Rudd camp was also considering sending a delegation of senior figures to the Prime Minister's office to call on her to declare the leadership vacant, with a second option being a petition of signatures from caucus members for a spill. Caucus rules allow for a leadership ballot when a minimum one-third of caucus members have put their names to a petition. However, this option is seen as less likely because it requires MPs to show their hand even before a leadership ballot is secured. With MPs who are hostile to Ms Gillard, and convinced the government is headed for annihilation under her leadership, itching for a showdown, the tactic of choice to date has been one of maximum pressure to create a more or less permanent sense of chaos in the hope of forcing the Prime Minister to move to clear the air. However, Ms Gillard's backers say this will not happen and they insist the embattled Prime Minister will lead them to the September election. As the smouldering leadership tensions burst into the open for the first time, ministers and influential backbenchers loyal to Ms Gillard began calling colleagues to shore up her base, with phones running hot.

As the penultimate sitting day of Parliament wore on, it was understood Mr Rudd's backers were also trying to crack Ms Gillard's support base, particularly in the Victorian Right faction where the influence of key ministers Bill Shorten and Stephen Conroy has ensured a swath of votes remain locked in behind the Prime Minister. Parliament breaks on Thursday for six weeks before the budget. Mr Fitzgibbon's comments suggest the chances of a leadership change could turn on what happens on the final day before the parliamentary recess - traditionally the most dangerous time for wounded leaders. Loading Ms Gillard's supporters were increasingly confident on Wednesday evening that they had seen off the potential challenge, clearing the way for the government to refocus on preparing for the election, which she has said will be on September 14.