Victoria's corruption watchdog has been asked to investigate Premier Jacinta Allan.

The under-fire premier is accused of personally intervening to ensure a CFMEU backed consortium was hired to deliver one of the state's Big Build projects.

The complaint, lodged by shadow Attorney- General James Newbury, has asked Victoria's Independent Broad-based Anti-corruption Commission to investigate Ms Allan and any of her staff involved in the deal when she was transport infrastructure minister in 2022.

"IBAC has the power to look at what the premier and her office may have done in relation to these decisions," Mr Newbury told reporters.

"So we are calling on IBAC to investigate what has the premier been up to, what did her office do, what type of leaning in did she do to push contract decisions with a CFMEU and with the Labor company that saw a blowout in costs, a company which has since been charged with serious financial crimes."

Corruption allegations continue to plague Victoria's government, prompting urgent calls for a royal commission into criminal networks embedded within the construction industry.

The Big Build corruption scandal involves allegations that organised crime figures and bikie gangs have infiltrated Victoria's major infrastructure projects through the CFMEU construction union.

Investigations indicate extortion, violence and billions of dollars in bribery-inflated project costs, with funds allegedly siphoned into ghost shifts, nepotism and payments to underworld figures such as Mick Gatto.

The Australian Federal Police is probing corruption, money laundering and organised crime within Victoria's construction sector.

Ms Allan, who has repeatedly said allegations of construction sector illegality should be referred to police, consistently rejects calls for a royal commission.

"Anyone who is calling for a royal commission is actually calling for delayed action, calling for action that would see the culture not change," she said on Monday.

She has also been steadfast in her commitment to grant the corruption watchdog "follow the money" investigative powers.

But any such legislation will not be implemented until a review process is completed by the end of 2027.

Among the loudest voices calling for a royal commission is Geoffrey Watson SC, the barrister who oversaw a months-long investigation into the CFMEU in 2024.

The integrity expert's report estimated $15 billion might have been lost to wrongdoing on taxpayer-funded construction sites in Victoria.

Ms Allan has previously disputed that figure while members of her government have cast doubt on Mr Watson's methods.