Police executed a search warrant on the Canberra headquarters of the CFMEU yesterday, as investigations into alleged bribery and corruption by senior union leaders gather pace.

ACT police and staff from the royal commission into trade union corruption searched the union headquarters for evidence of crimes including bribery and blackmail.

Key points: Police seize computer files, hardware at Canberra CFMEU headquarters

Police seize computer files, hardware at Canberra CFMEU headquarters CFMEU slams raids as "political stunt"

CFMEU slams raids as "political stunt" Witnesses have alleged CFMEU officials demanded bribes

The police action comes days after Fairfax Media reported police in three states are investigating senior CFMEU leaders as a result of evidence gathered by investigators working with the royal commission.

Police have confirmed they seized computer files and hardware.

"The raid by the Australian Federal Police on the ACT branch of the CFMEU yesterday was obviously under the direction of the royal commission," the union said in a statement.

"It smacks of overkill and a waste of police resources at a time when police are stretched dealing with more pressing issues in our community including terror related activities.

"This is nothing other than a political stunt by the royal commission which is desperately trying to defend its credibility and purpose."

Fairfax reported the Victoria Police taskforce, Heracles, had recently taken witness statements from multiple construction industry figures as detectives attempt to charge Victorian CFMEU secretary John Setka and his deputy, Shaun Reardon, with blackmail in connection to the union's campaign against concrete firm Boral.

Police witnesses have reportedly been advised by detectives that a criminal brief against Mr Setka and Mr Reardon has been completed and that police were waiting to receive legal advice before laying charges.

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Witnesses at recent hearings in Canberra alleged the CFMEU officials in the ACT demanded bribes and blackmailed builders and tradesman.

A former official of the union, Fihi Kivalu, has been charged with blackmail, as has union official and former Canberra Raiders rugby league player John Lomax.

Former Canberra Raiders rugby league player John Lomax has been charged with blackmail. ( ABC News: Matthew Doran )

The offence Lomax is charged over does not relate to evidence already heard by the commission.

A Canberra policeman also gave evidence that Lomax tried to intimidate him at a building site after he went there to investigate reports CFMEU officials were trespassing.

The royal commission is in limbo as the commissioner, Dyson Heydon, decides whether he will step down in response to submissions from the ACTU, CFMEU and AWU, which argue that there is a perception of bias because Mr Heydon agreed to speak at a Liberal Party fundraiser.

Mr Heydon says he will announce his decision on Friday.