Top Labor figures believe "it's time" for outspoken federal MP Michael Danby to retire as anger over his taxpayer-funded attacks on an ABC journalist sparked fresh speculation about his future.
Federal and state ALP sources say they expect Mr Danby to announce his retirement ahead of the next election - but are preparing for a possible preselection challenge in case he does not.
Mr Danby ramped up his attacks on the ABC's Middle East reporter Sophie McNeill on Thursday with a second ad - funded with his electorate allowance - in the Australian Jewish News.
The ads have accused McNeill of an anti-Israel bias in her reporting. Mr Danby is an ardent supporter of Israel who holds the seat of Melbourne Ports - which has a large Jewish community - on a margin of just 2 per cent.
But party figures from Opposition Leader Bill Shorten down are deeply unimpressed with Mr Danby's attacks on McNeill. In a heated phone conversation on Wednesday Mr Shorten instructed Mr Danby - his factional ally - to withdraw the latest ad but it had already been sent to the printers.
The controversy has hardened the resolve of Mr Danby's critics, who want him to end his 20-year hold on the seat of Melbourne Ports and make way for someone better able to fend off the Greens.
"The expectation here is it's time," one state source said. Another said they believed the party would increase its margin with another candidate, saying Mr Danby had become too divisive to resist the Liberals and the Greens.
Federal party sources say they are fed up with Mr Danby using political capital to attack the media rather than the government. But his critics are unwilling to publicly criticise him, fearing it will cause him to dig in and run again.
A decision by Attorney-General George Brandis to appoint Mr Danby's wife - lawyer Amanda Mendes Da Costa - to a well-paid job on the Administrative Appeals Tribunal has further fuelled speculation he will retire.
The ABC's director of news Gaven Morris hit back at Mr Danby on Thursday.
"We've gone from unfair and wrong accusations in the first ad to the bizarre in the second, which tries to link two completely separate events. It shows the extent to which this is a personal attack, rather than any fair assessment of the value and accuracy of the ABC and Sophie's reporting," he said.
Former Labor foreign minister and NSW premier Bob Carr - who regularly clashes with Mr Danby over foreign policy issues such as Israel-Palestine - said Mr Shorten should make him apologise for his attacks on McNeill.
"Can't believe Danby used more taxpayer funds on second Aus Jewish News ad attacking ABC coverage," he tweeted. "A weekly injection of taxpayer money? Should guarantee editorial endorsement in unlikely event Labor runs him again."
Linfox executive Ari Suss was once thought to be Mr Danby's likely successor in the seat but is said to have cooled on the idea. Andrews government staffer Josh Burns has also been tipped as a potential candidate.
Mr Danby did not respond to requests for comment on Thursday.