Julia Gillard is being assured she has the numbers to resist any push from Kevin Rudd but the likely failure of the more contentious media Bills looms as another pressure point for the Prime Minister.
Senior factional heavyweights loyal to Ms Gillard insist she has a "very comfortable majority" in the 102-member Labor caucus.
But no one on either side of the power wrestle denies the contest has tightened considerably since last year's leadership ballot, won by Ms Gillard 71 votes to Mr Rudd's 31.
Neither side is doing any official counting of numbers but the loyalties of Labor MPs and senators are being unofficially assessed.
One Gillard backer said the PM had at least 55 votes, with Mr Rudd on a maximum of 40. On this count, seven are considered as waverers or undecided.
The Rudd side believes the former PM has more than 45 votes but, in the event of another leadership spill, more votes would trickle in.
The PM's strategists suspect Mr Rudd would challenge if he had the numbers, notwithstanding his pledge not to do so.
"Let's face it, if Rudd did challenge, breaking a promise not to challenge would be a victimless crime," one minister said.
But Mr Rudd was keen to quash this theory, releasing a statement, that "unlike others who have used the phrase, when I say will not challenge for the leadership, I mean it".
Chief Government Whip and key Rudd ally Joel Fitzgibbon said it would be "silly to tell people that there's nothing going on".
"Obviously, internally people are looking at the polls and they're expressing concern about the future of the Government," he said.
"The Prime Minister continues to enjoy the support of the party room and I think people have proved themselves a little bit over-excited by speculating there'll be a change this week or necessarily before the next election."
As happened during last year's leadership tension, there was talk a Rudd backer was seeking 34 signatures to force a special caucus meeting to spill all leadership positions but a Labor senator fingered by his colleagues denied this was the case.
Foreign Affairs Minister Bob Carr said reports he was being encouraged to fly home from the US early were "entirely false".
Senator Carr is understood to be greatly annoyed at being identified as having lost confidence in the PM.