BOB Carr, the outgoing foreign affairs minister, is likely to resign from the Senate when he returns from an overseas trip, according to reports.

The Australian Financial Review writes that Mr Carr is expected to tender his resignation after he returns from the G20 summit in Russia.

Australian Worker's Union Secretary Paul Howes - one of the 'faceless men' who toppled Kevin Rudd from the top job - is considered his likely replacement.

In fact, Mr Howes's published diary of the 2010 election campaign was titled Confessions of a Faceless Man.

The former premier of NSW was Prime Minister Julia Gillard's star pick for the Senate in March 2012 after the resignation of Labor powerbroker Mark Arbib left a casual vacancy.

Mr Carr is still overseas after having met with leaders including US President Barack Obama at the summit.

ALP president Jenny McAllister says it's a matter for the party's NSW branch.

"Paul is obviously a fine contributor and he represents the labour movement very well at the moment in his current position and he would be a great representative for the labour movement in another role," Ms McAllister told Sky News on Monday.

"But I'm sure there will be plenty of people putting themselves forward should a vacancy come about."

Mr Carr secured re-election at the weekend.

Comment is being sought from Mr Howes and the NSW ALP.

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