The biggest move in the wake of the royal commission into trade unions has come in the form of charges against CFMEU leader John Setka.

Construction, Forestry, Mining and Energy Union (CFMEU) chiefs John Setka and Shaun Reardon could face 15 years in jail after being charged with blackmailing concrete company Boral.

Mr Setka was pulled over by police in Melbourne on the weekend and taken to police headquarters to be charged.

The charges relate to claims that Mr Setka and Mr Reardon sought to harm Boral's business when the concrete firm refused to give in to demands not to supply concrete to one of the CFMEU's industrial enemies, developer Grocon.

The court will hear allegations that Mr Setka and Mr Reardon arranged for other construction firms to boycott Boral when it refused to join the union’s campaign against Grocon.

The CFMEU's dispute with Grocon came to a very public head in 2012 at a blockade of Grocon's huge Myer Emporium worksite in Lonsdale Street, Melbourne.

The rally erupted into violent clashes with police that forced the shutdown of CBD streets.

It is alleged that a blackmail plot was put into action on April 23, 2013, when Mr Setka and Mr Reardon met with Boral employees Paul Dalton and Peter Head.

Police allege Mr Setka told the Boral representatives at the meeting that the company was in the middle of the CFMEU's fight with Grocon, but that the union could easily target Boral if Mr Setka's demands were ignored.

“We are at war with Grocon, and in a war you cut the supply line,” Mr Setka allegedly said.

The royal commission has previously alleged that Mr Setka may have committed the criminal offence of blackmail, contrary to section 87 of the Crimes Act.

The commission said Mr Reardon may have also committed the offence of blackmail, or aided and abetted Mr Setka and therefore could be liable as an accessory pursuant to section 323 of the Crimes Act.

CMFEU national secretary Dave Noonan has unleashed on the police's handling of the arrests, which he said “reek of overkill” and should not have been done in the presence of the men’s families.

“500 Swanston St is the address of the Victorian branch of the union where both men work from about 7am every weekday. I thought the police might be able to Google that, but apparently not,” he said.

“The CFMEU has co-operated with every request from the royal commission, and the police could have conducted their business at the office during working hours,” he said.

Mr Noonan said it was clear someone was going for maximum political damage by arresting the pair in the dramatic way the police did.

The union figures are expected to plead not guilty.

Mr Setka and Mr Reardon have been released on bail after being charged on Sunday morning, and will appear in Melbourne Magistrates Court on December 8.