Brandis to quit Senate, move to UK

Deputy Prime Minister Barnaby Joyce will vacate his agriculture portfolio to Queensland backbencher David Littleproud, to pick up transport and infrastructure from his Nationals colleague Mr Chester.

He later said the composition of the ministry had to take into account "matters of geography" and Mr Joyce had insisted Mr Chester, a Victorian, make way for more Queenslanders given a large proportion of the Nationals party room comes from the sunshine state.

Mr Turnbull defended the decision to promote Mr Littleproud directly to Cabinet where he will be Agriculture Minister.

"It's a ministry that showcases the depth of the Liberal and National team, with well-earned promotions for talented individuals, and a number of young and upcoming MPs bringing new skills and energy to the frontbench", he told reporters.

Kelly O'Dwyer will take Cash's former role as Minister for Women.

Prime Minister Malcolm Turnbull has made significant changes to his ministry.

The other cabinet minister said to be in the running for the job of Attorney-General was Employment Minister Michaelia Cash; however, she has been damaged by the recent resignation of a staffer, who tipped off media about a raid on union offices, and accusations she initially misled Parliament over the matter.

Tehan moves from veterans' affairs to the minister for social services, taking over from Porter.

McKenzie has jumped straight into being the Minister for Sport, Rural Health & Regional Communications, while justice minister Michael Keenan will now fill the roles of Minister for Human Services and Minister for Digital Transformation.

Attorney-General George Brandis is reportedly leaving the Senate to take over as the next UK High Commissioner.

In a press conference on Tuesday, Turnbull paid tribute to Brandis' 17-year career.

The finance minister, Mathias Cormann, will add the role of special minister of state, after Scott Ryan became the Senate president.

Chester said it had been an "enormous honour and privilege" to serve in cabinet, adding that he was "sorry we won't get to finish some of the jobs we've started".

"How else can you explain a competent minister like Darren Chester being demoted?"

Shorten said it was no accident that Laundy had day-to-day carriage of workplace relations.