Greens fear Senate losses in election

The Greens are talking down the chances of holding all of their Senate seats at the next election but believe some lower house gains are possible.

Greens senators and lower house MP Adam Bandt received an election planning briefing in Canberra on Monday.

It came as Prime Minister Malcolm Turnbull told his coalition party room on Tuesday a double-dissolution election was a "live option" and an election would be called within six months.

A Greens source said the party's Senate position was strongest in Victoria, Western Australia and Tasmania.

The NSW seat held by Lee Rhiannon remained winnable, but the vote was soft in Queensland and South Australia.

Demographic change was the key concern in Queensland and independent senator Nick Xenophon was a threat to the party's position in SA.

In the lower house, the Greens will be targeting the Victorian seats of Batman and Wills, as well as the NSW seats of Grayndler and Richmond, regions where the party made gains in the state election.

Two other Victorian seats, Higgins and Melbourne Ports, and the WA seat of Fremantle are also in the party's sights but are not considered likely gains.

The source said the party's election platform would be fully costed, based on winding back superannuation tax breaks, capital gains concessions, the diesel fuel rebate and ensuring multinationals pay a fairer share of tax.

Greens research is picking up unrest with Mr Turnbull's lack of action on issues he supports, including same-sex marriage and climate change.

There are also concerns he will not stand up to the conservative "dinosaurs" in the party room.

"Turnbull failing to deliver will be the story," the source said.

The party is very confident of holding Mr Bandt's seat of Melbourne.

An estimated one-third to one-quarter of preferences are expected to come from coalition voters.