Labor leader Bill Shorten is pushing strongly for a woman to replace retiring MP Kelvin Thomson, as fellow party heavyweight Senator Stephen Conroy attempts to manoeuvre his own man into the safe Victorian seat of Wills.

It is understood that Mr Shorten favours the preselection of a female candidate for the seat, which would bring Labor closer to fulfilling its self-imposed goal of women holding 50 per cent of all positions in the party within 10 years.

Key points: Bill Shorten wants a female candidate to replace Kelvin Thomson

Bill Shorten wants a female candidate to replace Kelvin Thomson Rudd government adviser Peter Khalil believed to be interested in running

Rudd government adviser Peter Khalil believed to be interested in running Former Federal Senator Mehmet Tillem appears to be frontrunner

Former Federal Senator Mehmet Tillem appears to be frontrunner Mr Tillem has been accused in the past of branch-stacking in the electorate

Although local members had expressed fears that the party's national executive would impose a candidate on them, there is growing confidence that a genuine preselection ballot will occur in Wills, which has the most party members of any Victorian seat.

A number of people are being touted as potential challengers for preselection, but few of them are women.

Journalist and Victorian Multicultural Commissioner Helen Kapalos has confirmed media reports that she was approached by senior Labor figures.

"Yes, I was approached, but quickly said no, I wasn't interested. Therefore I was surprised to see the news reports shortly afterwards," she told the ABC.

Former SBS executive and adviser to Kevin Rudd's government, Peter Khalil, is believed to be keenly interested in running for preselection, but with Senator Conroy backing Mehmet Tillem and Mr Shorten convinced of the need for a female candidate, he may struggle to attract the necessary support.

Got a confidential news tip? Email ABC Investigations at investigations@abc.net.au For more sensitive information: Text message using the Signal phone app +61 436 369 072 No system is 100 per cent secure, but the Signal app uses end-to-end encryption and can protect your identity. Please read the terms and conditions.

However, despite Mr Shorten's preference for a female candidate, the clear frontrunner for preselection still appears to be former Federal senator Mr Tillem.

The ABC reported earlier this year that an influential Labor local councillor with alleged links to Italian organised crime figures used then-senator Mr Tillem's office to improperly sign up members to the ALP, effectively creating a "ghost branch" of the party.

Moreland councillor Michael Teti was expelled from the ALP in July after it was revealed that he had worked for crime figure Frank Madafferi, and had allegedly supplied a gun to another criminal who is suspected of using it to threaten a woman.

Mr Tillem declined to comment when contacted, but the ABC is not suggesting he knew of Mr Teti's links to the Madafferi family or of his branch stacking activities.

Senator Conroy 'not commenting on party matters'

Mr Tillem, who is currently serving as chief of staff to state Labor minister Phillip Dalidakis, is closely tied to Senator Conroy, who is believed to be energetically backing his acolyte to take over from Mr Thomson in Wills.

A spokesman for Senator Conroy said he did not comment on internal party matters.

However, a loose alliance of other Labor figures is apparently equally adamant that Mr Tillem should not be given the opportunity to return to Federal Parliament.

Apart from Mr Shorten, these include factional opponents of Mr Tillem, but also others who believe Mr Tillem's links to branch stackers and back room deal-making is potentially dangerous to the party.

Mr Shorten's office did not respond to a request for comment.

Wills is essentially divided into two halves. The section closer to Melbourne's CBD, which takes in suburbs such as Brunswick and Coburg, is becoming more heavily populated by Greens voters.

While the northern half of the electorate is safer territory for Labor, with more elderly voters from a number of ethnic communities traditionally loyal to the party.

Labor insiders are concerned that the installation of Mr Tillem — with his reputation for Labor machine politics — will send younger Labor supporters into the arms of the Greens, who are making inroads every year as the gentrification of the seat creeps northwards.

The jostling over the Wills preselection comes with a backdrop of increasing angst over branch-stacking in Labor seats in Melbourne's northern and western suburbs.

In recent months, the ABC and Fairfax have revealed widespread use of pre-paid credit cards to anonymously sign up large numbers of party members, with the intention of influencing preselection battles.

An investigation by two party figures, Garth Head and Liz Beattie, is underway into how extensive the practice is, but internal critics have questioned whether the probe is genuinely independent, given the factional links of both Mr Head and Ms Beattie.

There is fear among some members that the final report will be a whitewash.

It was consternation over branch-stacking that led some in the party to fear that a candidate would be parachuted in by Labor 'head office', but that prospect now seems unlikely with the preselection expected in February.