Senior Victorian CFMEU officials accused of blackmail are seeking to have the charges struck out, saying they're an attempt to criminalise behaviour that occurs within an industrial dispute.

Victorian state secretary John Setka and assistant secretary Shaun Reardon are charged with blackmailing executives at Boral concrete in an alleged bid to cause a loss to construction giant Grocon.

Lawyers for the two men on Thursday argued the charges were not valid.

The charges ignore legislative provisions that say no criminal action is to be taken on secondary boycotts where there is an industrial conflict, the defence said.

Barrister Robert Richter, for Setka, described the charges as a “desperate attempt to criminalise behaviour that occurs within the context of an industrial disputes”.

“It was laid on a false basis,” Mr Richter told the Melbourne Magistrates’ Court.

“Your Honour is not obliged to conduct a committal hearing where it is an obvious waste of time and resources.”

The prosecution said the defence had inaccurately described the provision of the Act that prohibits criminal proceedings with regards to secondary boycotts.

“The phrase that our friends used does not appear in the provision,” prosecutor Peter Hanks said.

He also said the court does not have the power to stop the matter at this stage.

“Once the committal is before you, you are bound to proceed with the options that are given to you,” prosecutor Peter Hanks told Magistrate Mary Robertson.

These, he said, were to direct the accused to trial or to discharge them.

He later conceded there were some circumstances under which Ms Robertson could strike out the charges.

The argument was heard on what was to be the first day of the committal hearing – a process to test if there is enough evidence to support a conviction.

Ms Robertson expressed frustration that the challenges to the offences were only now being raised.

She will rule on the matter next Wednesday.