The Public Accounts Committee in Northern Ireland has said the tender process for a multi-million pound contract to re-build Belfast’s Lyric Theatre was potentially rigged and manipulated.
The committee said the way the contract was awarded was significantly flawed, and failed to adhere to the principles of good practice.
The landmark, whose patron is actor Liam Neeson, was re-built at a cost of nearly £18m (€21m), more than £5m (€5.9m) over the original estimate.
The bulk of the money, £12.2m (€14.4m), was put up by the Stormont Department of Culture Arts and Leisure.
The £11m (€13m) building contract was awarded to the firm of Gilbert Ash Limited.
The PAC said it had been left with the very strong impression that the tender process was both rigged and manipulated.
The committee said adjustments to the tender submissions by those running the process resulted in Gilbert Ash jumping from fifth out of five bidders to first place.
It also identified a potential conflict of interest in that the builders had given the Lyric a donation of £150,000.
The committee said they believed the department and the Arts Council did not discharge their duty properly and failed to ensure the proper use of public funds.
Committee Chairwoman Michaela Boyle said: "The quality of the rebuilt Lyric Theatre is undisputed; we recognise that it is a highly impressive theatre and that it has deservedly won a number of prestigious awards.
"However, the end does not justify the means. My committee has found that there were significant departures from good practice in the award of this £11 million contract, and this is completely unacceptable."
The Lyric Theatre said it completely rejected what it called "the wholly unevidenced claims made against the project".
A spokeswoman from Gilbert Ash said the firm did not have any control over the adjustments made to the tender submissions.
"We had no control over the adjustment to tender costs made during the procurement process - a practice that is standard in our industry to allow for like for like comparison of bids," she said.
In regard to the firm's donation to the Lyric, she added: "We are committed to positively impacting on the community around us.
"As such, we were delighted to sponsor the Lyric theatre, a fantastic arts venue and a major contributor to cultural life in Northern Ireland.
"We implemented a similar sponsorship partnership when working on the Waterfront Hall project and may follow similar practice in the future, should the opportunity arise."