Yet another multi-million dollar inquiry has been launched in Queensland, this time into the state's racing industry.

The government says it's not a political witch-hunt to embarrass the former Labor government, but an independent investigation into alleged mishandling of massive contracts.

Attorney-General Jarrod Bleijie expects former premier Anna Bligh and her treasurer Andrew Fraser to be called, but ultimately it will be up to the yet-to-be named Commissioner to chose witnesses.

"I believe former government officials have questions to answer," Mr Bleijie said.

The $3 million Commission of Inquiry will examine how Racing Queensland awarded 36 contracts totalling $150 million to Contour Consulting Engineers without being put to tender.

About $60 million of the works were completed before the Newman government froze the program.

It will also investigate if Racing Queensland improperly influenced the government to transfer $20 million for infrastructure projects two days before it went into caretaker mode.

The inquiry will also examine if four executives illegally received golden handshakes.

Mr Bleijie defended launching the inquiry despite work already done by the Australian Securities and Investment Commission and a forensic audit by Deloitte Touche Tohmatsu.

"The taxpayer ought to know that they got value for money, where the money was spent, who authorised the expenditure," he said.

"This has got health payroll bungle all over it again."

It is the fifth major inquiry announced in the past year.

Former federal treasurer Peter Costello was paid $3300 a day to audit the state's books, and the child protection inquiry and the Queensland Health payroll inquiry have multi-million-dollar price tags.

The review of the Crime and Misconduct Commission however only cost taxpayers $311,000.

Mr Bleijie says it is money well spent.

"There is no use-by date for justice."

Opposition Leader Annastacia Palaszczuk said if the government was going to launch an inquiry it needed to stop making prejudicial comments about former Labor MPs.

"It's always about re-prosecuting issues from the past."

"It is not for the government of the day to draw up its political witch-hunt list."

Mr Fraser has previously said a $20 million payment to Racing Queensland just two days before the Bligh government went into caretaker mode, had been approved in the budget, and all decisions were made in accordance with Treasury advice.

He took to Twitter again to urge the government to release the Treasury briefing note to back up his stance, but Mr Bleijie says he'll have to pay for a Right to Information application like every other Queenslander.

Former Racing Queensland chair Bob Bentley welcomed the inquiry and believed it would clear his name.

"We'll get it out on the table once and for all," Mr Bentley told AAP.

"People making all these accusations will have to put up or shut up now."

The inquiry will begin on July 1 and will run for three months.