CFMEU protest over Vic blackmail charges

A sea of fluorescent yellow and orange has taken over Melbourne's court precinct as CFMEU members protest two of its leaders being charged with blackmail.

A heavy police presence surrounds Melbourne Magistrates Court on Tuesday morning and the protest by construction workers has already caused traffic chaos, blocking William Street between Lonsdale and LaTrobe Street.

CFMEU Victorian secretary John Setka and his deputy Shaun Reardon are due to face court charged with one count each of blackmail stemming from allegations raised before the Royal Commission into Trade Union Governance and Corruption.

Both are expected to plead not guilty on Tuesday, the CFMEU says.

CFMEU National secretary Dave Noonan said Setka and Reardon were two workers voted by their peers to represent them and should not be punished for that.

"The fact they have been singled out in this way is an absolute disgrace," Mr Noonan told the crowd.

"We're not going to stand by and allow it to happen."

The protest coincides with mounting pressure on Premier Daniel Andrews to distance his government from the construction union.

"He's got to expel these people from the Labor Party," opposition leader Matthew Guy told reporters outside parliament on Tuesday.

He said the CFMEU's actions were "just dominating the government".

Setka has thanked the crowd for their support on his way to court.

"This will never be forgotten," he said.

The gathered group booed as he described being arrested in front of his kids on Sunday.

Setka also called the royal commission into trade union corruption a "disgrace".

Speaking to reporters as he walked into court, Setka said he was overwhelmed by the support.

"It's just the beginning," he said of the pending court process.

Asked whether he had anything to say to Boral, he said: "Stop killing people at work".