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.

David Leyonhjelm, Fraser Anning and Cory Bernardi have formed a voting alliance. Credit:Andrew Meares

"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.