By Dominic Giannini and Kat Wong in Canberra

Politicians are nervously waiting by their phones hoping for a cabinet promotion, as two senior ministers prepare to step down.

Labor heavyweights are meeting to decide who will step up to fill two Left faction positions in cabinet after the resignations of ministers Linda Burney and Brendan O’Connor.

Both will retire at the next federal election, due by May 2025, but bow out of cabinet immediately to make way for fresh legs in the run-up to polling day.

Speculation has swirled around a handful of potential replacements, but NDIS Minister Bill Shorten said voters would have to wait and see.

“Loyalty is not always rewarded but merit should be,” he told the Today show on Friday.

As assistant minister to Ms Burney, indigenous Senator Malarndirri McCarthy is widely regarded as her heir apparent and is also from the Left faction.

NSW Left faction senators Tim Ayres – a close ally of Mr Albanese – and Jenny McAllister are considered strong performers while Queensland Senator Anthony Chisholm is also in the mix.

All three are assistant ministers.

The future of Home Affairs Minister Clare O’Neil is uncertain, with talk she could be moved sideways into another ministry to allow someone such as frontbencher Murray Watt to take over the portfolio.

After months of criticism over asylum seekers released from immigration detention, Immigration Minister Andrew Giles could also change positions.

The full extent of Mr Albanese’s cabinet shake-up will be revealed on Sunday, but Opposition Leader Peter Dutton has already launched a pre-emptive attack.

“If Andrew Giles doesn’t get the flick, I don’t know who does,” he told the Today show.

There is a view more senators need to be brought in as ministers to help share the workload during busy parliamentary weeks and estimates, when they represent ministers from the lower house.

Lower house MPs Ged Kearney and Julian Hill are also being mentioned by Canberra insiders, while Northern Territory MP Marion Scrymgour could pick up Senator McCarthy’s assistant indigenous affairs position.

Assistant ministries are handed out by the prime minister.

A Senator McCarthy promotion would leave one cabinet spot open if Mr Albanese decides to maintain its current size.

Outer minister Pat Conroy, another Albanese confidant, is a strong contender for promotion, which would leave an outer ministry spot available and clear the decks for a Left senator call-up.

The NSW and Victorian party branches will also need to roll out pre-selection processes for new candidates.

Ms Burney won the inner-Sydney seat of Barton with more than 50 per cent of the primary vote and more than 65 per cent overall at the 2022 federal election.

“The most important thing… is for me to support whoever it is in the role and to give them the space to be able to chart their own path and carry on the many important jobs that we’ve started,” she told ABC radio.

Mr O’Connor’s outer Melbourne seat of Gorton is held on a 10 per cent margin and considered a safe seat but recorded a more than 10 per cent swing against Labor’s primary vote and four per cent overall swing to the Liberals in 2022.

Eyes on Sunday’s reshuffle, fears on Wednesday’s inflation