The Greens have elected Adam Bandt to the deputy leadership following the resignation of long-time party leader Bob Brown earlier today.

Mr Bandt is replacing Christine Milne, who has been elevated to the leadership after Senator Brown's decision to quit after 16 years in the Federal Parliament.

It is believed Scott Ludlam and Sarah Hanson-Young also stood for the deputy's position.

Mr Bandt, the Greens' sole member in the House of Representatives, says he is grateful for the party's support.

"I look forward to working with Christine Milne in providing stable leadership in this new phase in the growth of our party," he said.

"It will be a privilege and honour to work as deputy leader and support Senator Milne's vision, integrity and experience in minority government."

He says his appointment reinforces the Greens' role as the third force of politics, with leadership now in both houses of Parliament.

"We are ready to tackle the challenges of the future and we will continue to be the centre for innovation in the Australian Parliament," he said.

Senator Milne says Mr Bandt shares her passion to start a national conversation about what Australian society values.

She says she is delighted with his appointment.

"I'm really looking forward to working together with him as well as our whole party room," she said in a statement.

"Adam has a tremendous grasp of the issues confronting Australia, and I know he shares my passion to start a national conversation about what an Australian society values and wants to promote as we face the challenges of the century."

Mr Bandt was elected as the Member for Melbourne at the 2010 federal election, a seat formerly held by long-time MP and Labor heavyweight Lindsay Tanner.

Replacement

Senator Brown will officially step down as a senator in June.

He says he is confident the party will flourish in his absence.

Tasmanian Greens leader Nick McKim has ruled himself out of replacing Senator Brown in the Federal Parliament.

"I've got a big job to do here in Tasmania," Mr McKim said.

"I've always said that I would go full term... and lead the Greens, with the support of my party room assumed, to the next state election and that remains my priority.

"But also I feel very strongly personally that Tasmania is midway through an economic transition. It needs to be managed, including with Greens input."

Other possible replacements mentioned in local media include former state leader Peg Putt and the candidate in the federal seat of Denison, Geoff Couser.

Surviving

Opposition Leader Tony Abbott thinks the Greens might have a hard time surviving beyond Bob Brown.

"I think he's had a role in respect of the Greens a little bit like that of Don Chipp in respect of the Australian Democrats and I think these will be turbulent times for the Greens," Mr Abbott said.

"I'm not going to be a hypocrite and say that I agreed with Bob Brown or supported Bob Brown, but I think you have to respect the fact that he has led the Greens for a long time."

There will not be a change in the deal negotiated with the Prime Minister to form a minority government, as Senator Milne co-signed the agreement as deputy.

Prime Minister Julia Gillard says she has not always agreed with Senator Brown's views but has paid tribute to his service.

"You'd have to say he's lived a life in Australian politics, an interesting life, a life starting with his environmental activism around the Franklin Dam and leading him all the way to the Senate and to leadership of a political party that he created, the Australian Greens.

"Bob Brown has made a remarkable contribution to Australian politics."