Opposition Leader Bill Shorten has refused to expel Joe McDonald from the ALP, after the unionist threatened a worker with his fist to coerce him into an unlawful strike.
Mr Shorten condemned Mr McDonald's behaviour and said there was no place in the modern workforce for a "dinosaur" like Mr McDonald.
"He is a repeat offender who keeps breaking industrial law - costing union members hundreds of thousands of dollars in fines and causing grief and lost time in the construction industry," Mr Shorten said.
"There is never an excuse to break the law - not in boardrooms or on building sites."
But Mr Shorten refused calls from Federal Employment Minister Eric Abetz to expel him from the ALP as Kevin Rudd did in 2007.
Court documents this week show Mr McDonald, the assistant State secretary of the Construction Forestry Mining and Energy Union, held a worker at the Mundaring water plant by the neck and raised a fist in a threatening manner in a bid to coerce him to strike illegally.
Mr McDonald had warned some workers there would be "world war three" if they did not join the strike and the union would get them thrown off every construction site in Perth, and that it would "be the end of your company".
It was among several strikes to cost the union almost $700,000 in compensation and penalties, as well as a three-year ban for Mr McDonald from Brookfield Multiplex sites.
WA Labor leader Mark McGowan said Mr McDonald's actions were "completely unacceptable" but expulsion was a matter for the party.
Some CFMEU members phoned _The West Australian _to call for Mr McDonald's dismissal from the union. In a sign of their fear for the consequences, they declined to be named.