Mr Rattenbury, the only Greens MLA to have been returned to the ACT Assembly in the cliffhanger Territory election, is deciding whether to support Labor or Liberal in the next minority government.

With both major parties deadlocked on eight seats, Mr Rattenbury as the only other MLA elected finds himself in the position of ACT kingmaker. And while he is not short of advice about who he should support, the former ACT Assembly Speaker said he is looking forward to more talks with the Greens' federal parliamentarians about the issue.

''Certainly I'll have discussions with Christine Milne,'' he said.

''I have good relationships with all my federal colleagues. They are people that I do talk to about strategy … but they don't have a formal role. The way it works in the ACT Greens constitutional set-up is that the parliamentarians have the ultimate say on these issues.''

But it is clear the federal Greens will play a big role in ACT politics - at least during the next week or so.

The electoral commissioner will declare the polls on Wednesday and the ACT Assembly must then sit within a week of that declaration.

That gives the Greens ample time to decide which party to shepherd into government.

The ACT Greens membership met in Canberra yesterday, and during a two-hour meeting established a sub-committee to consult with Mr Rattenbury about his decision.

''In addition to that there are people all over the place offering free advice,'' he said.

Following yesterday's separate meetings with Labor leader Katy Gallagher and Liberal leader Zed Seselja, the Greens will refine their position before more meetings with the other parties tomorrow.

''I'm keen to make a decision in a timely manner,'' Mr Rattenbury said.

''At the same time we're talking about establishing government in the ACT for the next four years, so taking an extra day or two to iron out some details is time worth taking.''

He has ruled out returning to the next Assembly as Speaker, saying that now the Greens have been reduced from four to one, he needs to have more say about legislation on the floor of the Assembly.

But he has not ruled out accepting a government ministry.

''Nothing like that has been ruled out. And nothing has been ruled in,'' he said. ''What counts here is what's best going forward. We're talking about things in terms of the Parliament and where the Greens best fit into that.''

Mr Rattenbury said he is genuinely open to both sides of politics and his main priority is to get the best representation for the policies the Greens took to the election.

To that end, a list is being drawn up to see which party can offer what.

Before politics in the elected sense, Mr Rattenbury was international political director of Greenpeace International. He said the management and negotiation skills he learnt in that role prepared him for the rough and tumble of political life.

Mr Rattenbury also said there were federal implications in the ACT election result that the Greens party nationally should note. ''There are undoubtedly some lessons to be learnt from the campaign,'' he said.

''But the stories of the demise of the Greens are being overtold.''

After her talks with Mr Rattenbury yesterday, Chief Minister Katy Gallagher said there was still work to be done on the ''big unresolved issue'' of the Greens' support.

''We had some very early discussions about how they were going to conduct themselves during the next week and the timetable for those discussions,'' she said.

''We also took the opportunity to discuss areas of policy where we did have crossover areas, where the Labor and the Greens policy could work very well together.''

The discussions represent a change from previous negotiations between Labor and former ACT Greens leader, Meredith Hunter, but Ms Gallagher said she was unperturbed, having worked with different members of the party over the past four years.

She has not ruled out the possibility of offering Mr Rattenbury a senior ministerial position, unlike Liberals leader Zed Seselja.

In a statement provided to The Canberra Times, Mr Seselja said he would meet the Greens member again in the coming days.

''I've had initial discussions with Shane Rattenbury and I look forward to further discussions over the next week,'' he said.

''I'm very hopeful the negotiations will be conducted in a genuine spirit of openness with a commitment to Canberra's future.'' with Stephanie Anderson