With the reshuffle announcement looming there is speculation Human Services Minister Brendan O'Connor could be elevated to cabinet to fill the vacancy left by Kevin Rudd, who moved to the backbench following his failed leadership bid.
Stephen Smith is being tipped to return to the foreign affairs job.
Defence sources suggest Tertiary Education Minister Chris Evans or Climate Change Minister Greg Combet - a former junior defence minister - could then fill Mr Smith's current role in the defence portfolio.
Parliamentary secretary David Bradbury appears in line to take on a ministry, possibly the assistant treasury portfolio being vacated by retiring NSW senator Mark Arbib.
Much of the frontbench is set to remain in place, however, despite five ministers having voted against Ms Gillard in the leadership ballot on Monday.
An online report that foreign policy commentator Michael Fullilove had been endorsed by the NSW Right to fill Senator Arbib's soon-to-be-vacant Senate seat was dismissed by the party's state secretary Sam Dastyari on Thursday night.
