Green Party co-leader Russel Norman said the "unravelling" of former Australian prime minister Kevin Rudd started, in part, because he was not able to make a deal with the Australian Green Party over the Emissions Trading Scheme (ETS).

A surprise revolt forced Rudd to call a party leadership vote today, just months away from national election, but he stood down before the vote took place.

Australia has shelved its ETS indefinitely.

"Kevin Rudd made a big deal that climate change was important and then he failed to get a deal signed up to actually introduce an ETS," Dr Norman said.

The super profits tax on the mining industry was also a factor but failure over an ETS was the starting point, Dr Norman said.

"Had Kevin Rudd actually come to a strong agreement on protecting the environment he would still be Prime Minister of Australia."

Dr Norman said he felt sorry for Rudd and would write to him to express that.

New leader Julia Gillard would do a good job, he said.

"The key challenge for her now is going to be to build a good relationship with the Green Party in Australia in order to ensure that her Government has a strong majority in the senate both leading into, and out of, the election."