Claims of a spike in thuggish behaviour by unionists on construction sites have emerged as the Federal Government calls for higher penalties, according to the building industry watchdog.
Nigel Hadgkiss, who heads Fair Work Building and Construction, said unions across the country had become increasingly aggressive during his 10 months as director. He claimed there was growing anecdotal evidence of verbal abuse, stand-over tactics and physical confrontations on work sites.
It comes as the coalition calls for a three-fold increase in fines for those who break industrial law, taking penalties up to $34,000 for individuals and $170,000 for corporates such as unions.
"I believe there has been a general increase in thuggery in the industry in recent times, not just in abuse towards my investigators," Mr Hadgkiss said.
"The perpetrators of this behaviour need to know the FWBC takes it seriously and will refer it . . . for prosecution."
Mr Hadgkiss said the $1.2 billion children's hospital in Nedlands had emerged as a major "rallying point" for unions.
He revealed the FWBC had conducted 18 investigations into industrial matters at the site, which received up to 29 union visits a month. There were four current investigations at the site, involving allegations of coercion and industrial action.
The construction union did not respond to calls yesterday.
UnionsWA Secretary Meredith Hammat said the allegations had not been proven, and claims of aggression and thuggery were at odds with their efforts to create fair workplaces.
"Unions are opposed to bullying of any kind in the workplace," she said. "It's just not on.
"Allegations can and should be reported and investigated by the appropriate authorities such as industrial bodies, the police or courts.
"Without evidence and proper investigation, general allegations alone risk unfairly harming the reputation of all working people across an industry."