Ms Le Couteur said she shared community concerns about the government's decisions on the Brumbies' former headquarters and an independent body could reassure the public that decisions were made properly.

Ms Le Couteur's move is an early sign that her election to the ACT parliament in October could signal a significantly more activist and critical approach from the Greens, with her colleague Shane Rattenbury not forcing decisive action on the Brumbies issue over the past term while he has been a member of the Barr cabinet.

Ms Le Couteur was referring to a report in the Canberra Times about then sports minister now Chief Minister Andrew Barr's request for a debt waiver for the Brumbies in 2008 and 2009. The waiver was made on the basis of a suite of developments on site, including gym and physiotherapy centre, that never eventuated.

While Mr Barr was asking then chief minister Jon Stanhope to waive the debt in early 2009, the Brumbies were in talks with a private property developer about selling the site – although it remains unclear whether the private developer and Brumbies might have intended a development that included the promised community facilities.

Mr Stanhope told Mr Barr, on Treasury advice, that the debt should not be waived without a business case and detailed analysis of community and economic benefits. But that work was never done. Treasury documents say the Stanhope conditions were never conveyed to the Brumbies – an oversight Mr Barr has attributed his directorate.

The debt was waived by then Treasurer Katy Gallagher in August 2009, at the same time the Brumbies were getting a formal valuation on the land for sale to Amalgamated Property Group. After selling the land, now built out in apartments, the Brumbies moved to the University of Canberra.

The entire deal, including a waiver of $7.5 million in lease variation tax in 2012 and 2013, has been the subject of much controversy, this year culminating in a bitter split between former Brumbies boss Michael Jones and the club's board after Mr Jones ordered an audit into the transactions.

Labor and the Greens have promised an ACT integrity commission, but there is no certainty when it might be set up. Mr Rattenbury will chair an inquiry that will work out its powers and structure, and the Greens want a commission in place next year. But it might well take much longer, with Mr Barr not committing to a timeframe. It is also unclear what powers it would be given to look at historic allegations.

The Canberra Times does not suggest corruption in any of the government's Brumbies decisions. But Ms Le Couteur said the Greens were committed to "cleaning up the planning process" and ensuring the community could have faith in the government.

She said the decision-making suggested "a culture that lacks transparency and fails to put the community first".

"The ACT has clear laws governing approvals and waivers which are guided by what is in the public interest. It is concerning that it appears the ACT Government has failed to do its duty to take these responsibilities seriously."

Ms Gallagher, now a senator, said she was "satisfied with the information and advice provided to me by Treasury at that time about the community and economic benefits that the waiver would support".

She could not recall knowing anything of the negotiations between the Brumbies and Amalgamated Property Group.

Asked whether she believed, with the benefit of hindsight, that the $292,000 debt waiver and later $7.5 million lease variation waiver were justified and the right decisions, Ms Gallagher said she stood by her decisions, and she insisted Treasury advice had been followed at every step.

Comment has been sought from Mr Barr, who flew to Wellington on Monday.