The CFMMEU is hoping to use the Fair Work Act to scrap conditions for the $2.8 billion Sydney Metro Project.

The union has launched legal action to challenge several agreements in NSW and Victoria that exclude it from major infrastructure projects.

The Construction, Forestry, Maritime, Mining and Energy Union (CFMMEU) scored a recent victory when a Fair Work Commission full bench quashed a deal between CPB Contractors (formerly Leighton's) and the AWU for all civil projects in Victoria up to $1 billion.

The CFMMEU is also attacking a CPB agreement covering civil projects in NSW, including a $365 million contract for Pacific Highway upgrades.

The union has also sought to scrap workplace agreements covering tunnel and excavation works for John Holland-CPB-Ghella's joint venture for the Sydney Metro project.

The CFMMEU argues that the deal should be knocked back because it breaches freedom of association by preventing workers from sticking union stickers on their helmets.

Fair Work Commission deputy president Geoff Bull recently rejected the sticker argument, saying he could not see how prohibiting them was a breach of freedom of association.

“It is easier to envisage the potential for such a breach to occur where union stickers identify allegiance to an employee's membership of a building union compared to employees who may chose not to attach such labelling to their safety helmets,” he said.

“Where no 'union stickers' are permitted on safety helmets the issue does not arise.”

CFMMEU NSW has not said whether it will appeal that ruling.

Master Builders Association NSW executive director Brian Seidler said companies should not have to deal with “totally rogue” unions that “introduce all sort of restrictions to send companies up against the wall”.

“When companies go off and want to negotiate a greenfields project agreement they want to do it with people who are responsible, who show some sort of adherence to the law and not people who openly breach the law day in, day out,” he said.