"The Greens are now calling on (Prime Minister) Julia Gillard and (Opposition Leader) Tony Abbott to say let's now agree from henceforth we will have three-year terms," Senator Milne told reporters in Melbourne.
"We will all know that the election is going to be in that second week of September for henceforth three years.
"Wouldn't that be a great thing for the Australian people so we didn't have all the game playing that has gone on in the past?"
Senator Milne said the calling of the election had given Australians an opportunity "to take all political parties to task to talk about what sort of country we want".
"There will be a lot of discussion about what hollow promises may be made between now and then," she said.
She said the Greens had already announced a couple of policies this year, including raising the Newstart allowance by $50, as well as introducing a millionaires' tax to pay for it and to bring more equity to Australia.
"We are supporting addressing global warming and bringing about a transformation to renewable energy with all the jobs that (it) will bring across Australia," Senator Milne said.
"The Greens will be working very hard with the government to implement as much progressive policy as we can."
