Senior Liberal Vicki Dunne made the referral to ACT Integrity Commissioner Dennis Cowdroy on Friday.

It represents the second government land deal to be sent to the integrity commission for further scrutiny, after the now-defunct Land Development Agency's Glebe Park and Lake Burley Griffin purchases were referred late last year.

Mrs Dunne had wanted the ACT Legislative Assembly's public accounts committee, of which she is chair, to escalate the matter to the anti-corruption watchdog, after its long-running parliamentary inquiry into the 2014 deal raised more red flags about the government's conduct throughout the process.

But the move was thwarted by the committee's Labor member, Tara Cheyne and Bec Cody, who refused to support a referral when the inquiry handed down its findings on Thursday.

The Labor backbenchers said the auditor-general and Legislative Assembly inquiries into the land swap, along with media and opposition scrutiny, had failed to uncover "any evidence of corruption or inappropriate conduct" on the government's part.

But in her letter to Mr Cowdroy, which The Canberra Times has seen, Mrs Dunne said the matters raised in the two inquiries were grounds for a corruption complaint.

The two inquiries were similarly scathing of the handling of the deal, which ended with the ACT government paying the CFMEU-linked Tradies Club $3.9 million for a Rosevear Place block housing the union's old offices, as well as $45,000 for nearby land accommodating the Downer Club.

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In exchange, the government sold to the club the car park next to the Dickson Tradies for $3.5 million.

The audit report found the club received up to $2.6 million worth of concessions from the government as part of the deal.

Mrs Dunne said the committee's final report "traversed many areas which touch on the integrity of public administration".

These included the consistently poor record keeping, the departure from the scope of the original tender, the loss of value for taxpayers and the government's decision to waive commercial rent on a property acquired as part of the landswap.

Mrs Dunne told The Canberra Times that the "paucity" of written records of the negotiations and "contradictory" accounts from witnesses meant that there remained a number of unanswered questions about the dealings.

She pointed out that the anti-corruption watchdog had greater powers to interrogate witnesses than the committee.

She said there were still doubts over the legal status of the sale. Those questions arose because of the significant difference between what was proposed in the original request for tender and what was ultimately agreed to by the ACT government and the Tradies Club.

"There are so many things about this that don't add up," she said.