One Nation defector Fraser Anning has launched a spirited defence of Barnaby Joyce, fuelling speculation he is auditioning to join the Nationals in a bid to extend his political career - and potentially deliver the Turnbull government another crucial guaranteed vote in the Senate.

The conservative senator says the embattled Nationals leader has been a powerful advocate for rural and regional Australia and "Queensland cannot afford to lose him as its champion in the halls of power”.

Lashing out at critics of Mr Joyce as a "left-wing lynch mob", Senator Anning's defence is stronger than those offered by some of the Deputy Prime Minister's own party colleagues, who are now weighing whether to remove him as leader as a result of the political crisis unleashed by his affair with a staffer.

"It is obviously very regrettable that Barnaby Joyce's marriage has broken down but that is a private matter that should have nothing to do with his political role," Senator Anning said in a statement.

“Given the long history of sexual indiscretions of many other politicians with their staffers and each other the sudden rush of righteous indignation at Barnaby appears both hypocritical and politically motivated.”

The statement - an unusual intervention by an independent - has renewed interest in Senator Anning's future intentions.

Senator Anning left One Nation on his first day on the job, just minutes after being sworn in to replace dual citizen Malcolm Roberts. The shock move came after he had a spectacular falling-out with Pauline Hanson - his friend of 20 years - and any sort of reconciliation with One Nation is considered impossible.

But if Senator Anning wants to be re-elected he will need to attach himself to a party ticket, rather than run solo. It's understood he would consider joining the Nationals, Cory Bernardi's party or Bob Katter's party.

"I think he is auditioning for a number of people," a senior Nationals source said on Monday.

Shortly after quitting One Nation, Senator Anning started emphasising his "rural and regional" credentials. He also has historic links to the Nationals, with his family once close to the family of Joh Bjelke-Petersen.

He has had informal talks with National party figures but there has been no offer put on the table. Part of the problem is the Nationals could not promise Senator Anning a winnable spot on the Senate ticket at the election - due as early as the second half of this year - given the party's pre-selection processes.

But a source close to Mr Joyce said the Nationals could "philosophically accommodate" Senator Anning, even though he is further to the right than many in the party room. His hardline views have been likened to those of Nationals MP George Christensen, who taps into similar nationalist sentiments as One Nation.

Senator Anning has already formed an informal alliance with Senator Bernardi, along with crossbencher David Leyonhjelm. But Senator Bernardi's Australian Conservatives party is considered likely to run Christian crusader Lyle Shelton at the top of its Queensland Senate ticket at the next election.

And while Senator Anning is a Catholic he is not a regular churchgoer, which could put him at odds with some of Senator Bernardi's more evangelical supporters.

Senator Anning could opt instead to join Katter's Australia Party if there is a vacancy at the top of his Senate ticket. He has known Bob Katter for a long time and believes he is a powerful advocate for regional Queensland - but he has so far failed to get any senators elected, polling well behind One Nation in the upper house.

"I don't see him doing anything immediately," the senior Nationals source said. "He is obviously keeping his options open. But he will have to make his decision shortly."

The government last month managed to woo crossbencher Lucy Gichuhi to its ranks. She came into the Senate to replace Family First's Bob Day but chose to sit an an independent until joining the Liberals.