Prime Minister Scott Morrison is pushing ahead with his plan for a Royal Commission into the bushfires, and has identified a former defence chief as the man he wants to place in charge.

The news came on a dramatic first day of Parliament for 2020, which saw the Deputy Prime Minister fend off a leadership challenge, a new Greens leader elected and hours of tributes expressed in recognition of victims of bushfires.

The Prime Minister confirmed in his address to Parliament that he has written to state and territory leaders proposing former defence chief Mark Binskin lead a royal commission into Australia's summer bushfire disaster.

Mr Morrison told Parliament the move would "shine a light on what needs to be done to make our country safer".

He's asked premiers and chief ministers to provide feedback on the draft terms of reference for the royal commission.

As the Nationals battled over their leadership, the party faced criticism for focusing on internal tensions on a day set aside for recognising victims of bushfires.

Mr McCormack saw off a leadership challenge from Barnaby Joyce during a party meeting that also installed Cabinet minister David Littleproud as deputy leader.

Deputy Prime Minister Michael McCormack walks into the House of Representatives alongside Prime Minister Scott Morrison on February 4, 2020. ( ABC News: Sean Davey )

The Deputy Prime Minister said he shook hands with Mr Joyce and said "we will move on and work hard together".

Labor leader Anthony Albanese said the Nationals were being self-indulgent given the entire day of Parliament was dedicated to the bushfires.

Mr Morrison dubbed this season's fires as "Black Summer" in his address.

"These fires are yet to end and danger is still before us in many, many places, but today we together to mourn, honour, reflect and begin to learn from the Black Summer that continues."

The afternoon saw dozens of MPs pay their respects to victims of the fires, and express appreciation for the work of firefighters and others involved in the response.

The Greens elected its new leader, Melbourne MP Adam Bandt, with senators Larissa Waters and Nick McKim elected the co-deputies.

Re-live the first day back for 2020 below, as it happened.