Greens Leader Bob Brown says he has written to Prime Minister Julia Gillard offering a solution to the impasse on the emissions trading scheme.

Senator Brown says if Labor is re-elected the Greens would help the Government pass a carbon tax through the Senate within three months of polling day.

Senator Brown says the Greens deal would hold off on setting targets for emissions cuts until there is a global agreement on climate change, but would place a $23 per tonne price on carbon.

Senator Brown says the plan is similar to the idea put forward by the Government's former top adviser on climate change, Professor Ross Garnaut.

"But it doesn't bring in, at the outset, a carbon trading scheme," he said.

"It leaves that option open and it therefore doesn't become prescriptive about targets, which have been a stumbling block in the past."

Senator Brown says Ms Gillard should not wait to take action on climate change.

"She cited getting a carbon price in her first speech on Thursday as one of her priorities, and she knows, like all of us do, that quick action on climate change is wanted," he said.

Ms Gillard says she agrees there needs to be a price on carbon, but says there needs to be a "deep and lasting community consensus" to do it.

She has said she will work to get a price on carbon.

"I believe in climate change. I believe it's caused by human activity and I believe we have an obligation to act," she said.

Senator Brown says Ms Gillard could make a positive stand against climate change.

"I think Kevin Rudd with Penny Wong just simply failed to get together with the Greens and make the success that we could have had last year," he said.

"They were not motivated to do so, the signs were clear all the way through that they didn't see the Greens as good options, they preferred to go to the Coalition."