Former South Australian senator and Labor party powerbroker Don Farrell is poised to make a shock return to politics, putting up his hand to rejoin the ALP ranks in the Senate.

Key points: Senior ALP sources confirm Mr Farrell nominating for preselection

Senior ALP sources confirm Mr Farrell nominating for preselection Jay Weatherill threatens to quit if Mr Farrell successful

Jay Weatherill threatens to quit if Mr Farrell successful Simon Birmingham knocks off Cory Bernardi for top spot on SA Liberal Senate ticket

Senior ALP sources have confirmed Mr Farrell intends to nominate for preselection.

Mr Farrell has been contacted for comment.

The former secretary of the powerful shop assistant's union, the SDA, would be all but guaranteed a winnable position on the Labor ticket.

The 61-year old lost his seat at the last Senate election, after relinquishing top spot to senior left faction figure Penny Wong.

The relegation was largely seen as symbolic.

But when votes were counted, it proved to be much more significant, with independent Nick Xenophon outpolling Labor on primary votes.

In 2014, Mr Farrell made a bid to enter the South Australian parliament, offering to take over the safe seat of Napier from his friend and retiring MP, Michael O'Brien.

But the pre-election move was swiftly ended by the extraordinary intervention of Premier Jay Weatherill, who threatened to quit if it was successful, branding the shift as a "factional" try-on by "faceless men".

Mr Farrell vowed to go quietly, reflecting on his often used "Godfather" moniker and declaring there would be no sequel.

He subsequently moved into the public sector and opened a winery in the Clare Valley.

The ALP State Executive will today finalise its preference for order of the senate voting ticket for South Australia, which is expected to be endorsed by the National Executive tomorrow.

Mr Farrell is expected to claim second spot behind Penny Wong, relegating Senators Alex Gallacher and Anne McEwen to third and fourth.

SA Liberal Senate ticket gets a reshuffle

Meanwhile, Federal Education Minister Simon Birmingham has knocked off Cory Bernardi for top spot on the Liberal Senate ticket in SA.

The Cabinet minister and Turnbull supporter has pushed Senator Bernardi to second position, in a deal confirmed by the state executive of the Liberal Party on Tuesday night.

Assistant Agriculture Minister Anne Ruston will occupy third position, while Senator David Fawcett is number four on the ticket.

Liberal senator Sean Edwards, who claimed he secured a deal with former prime minister Tony Abbott to launch a tender process for the future submarine program, has been dropped to fifth position.

Senator Edwards would struggle to hold on to his place in the Upper House, with the independent senator Nick Xenophon expected to secure additional seats in the July 2 poll.