Opposition leader Alistair Coe also said he was "not convinced" the territory's contracted police force should be allowed to be exempt from such oversight, despite ACT Policing's push for the exemption.

His comments follow The Canberra Times reporting this week on a series of emails released under Freedom of Information which raised questions about whether or not Police Minister Mick Gentleman has privately supported the police's push.

Mr Gentleman met Chief Police Officer Justine Saunders earlier this year, a meeting which she later wrote included Mr Gentleman supporting her "approach" on the commission, but redactions in documents released mean it is unclear whether she was specifically referring to the exemption.

Neither Mr Gentleman, nor CPO Saunders, have answered questions directly on whether an agreement was reached on the exemption.

But both parties have said they agreed ACT Policing would provide an "independent submission" to the Legislative Assembly committee currently considering the anti-corruption commission.

Irrespective, Mr Coe said if any one area of government was not subjected to the commission's scrutiny, "it may open the door to other agencies also seeking an exemption".

"It is up to Mick Gentleman to provide a justification for why ACT Policing should not be subject to these investigations should a need arise," Mr Coe said.

"Given an investigation would only arise when there is suspicion of corruption, ACT Policing should have no concerns about such inquiries."

Mr Coe also said the need for an anti-corruption commission had been reinforced after recent revelations surrounding the government's purchase of land at Glebe Park in 2015.

In recent committee hearings related to that land purchase and other deals by the now-defunct Land Development Agency, Chief Minister Andrew Barr said he may have been "confused" when he signed a briefing note giving casino owner Aquis rights to that block.

But Mr Barr also told the hearing there had not been any government decisions to grant rights to the land to the casino owners.

Mr Coe said it appeared the "real reason" for the LDA buying the land at an "exorbitant price" was to sign it over to the casino.

"This assertion appears especially compelling when the government's official reasons for the purchase have gone absolutely nowhere," he said.

"The government proposed the site for either a stormwater pond, moving Parkes Way or for an Infrastructure Australia bid.

"None of these have progressed and the only viable development that seems to be in the pipeline is the casino."

However, a government spokesman has previously said there had never been a specific development proposal from the casino for that site and there still had not been.

While Aquis announced in 2015 it wanted to redevelop the existing casino by 2018, no development application has been lodged with planning authorities since then.

Greens MLA Shane Rattenbury, who chairs the committee inquiry, said he could not comment on any matter related to the committee's deliberations.

The committee's report is expected to be tabled in the Assembly later this month.