Labor elects rogue Nats MP deputy Speaker

Labor has delivered the Morrison government an embarrassing start to the parliamentary sitting week by getting a disgruntled Nationals backbencher elected as deputy Speaker.

Queensland MP Llew O'Brien had earlier quit the National Party following Barnaby Joyce's failed bid for leadership last week, but promised to still support the government.

Labor cheekily nominated Mr O'Brien for the position of deputy Speaker, which he won against his former Nationals colleague Damian Drum by 75 votes to 67.

Given there are only 64 Labor MPs in the chamber, the opposition is likely to have garnered the votes of all six crossbench members and five Nationals MPs in the secret ballot.

The role was up for grabs following a ministerial reshuffle prompted by Senator Bridget McKenzie's resignation from the ministry.

The Speaker's role is held by Liberal Tony Smith and Mr Drum was nominated as his deputy in line with the parliamentary protocol between the coalition partners.

Mr O'Brien had the opportunity to reject Labor's surprise nomination but in choosing to accept it, he put himself in direct contention with a former partyroom colleague.

"It will be an honour to serve this House as deputy Speaker," Mr O'Brien said after the win.

The new deputy Speaker also rejected Labor's assertion the government's numbers had been reduced because he had left the Nationals.

"I still remain a loyal and faithful government member."

Mr O'Brien, who represents the Wide Bay electorate, will look after the Federation Chamber in his new role.