FWBC is taking the union and six officials, including McDonald, to the Federal Court for allegedly intending to coerce 160 workers to strike at the Perth International Airport arrivals expansion project on October 22 last year, in breach of the Fair Work Act.

FWBC alleges that CFMEU officials organised for close to 100 people to occupy the entrance to the site – many holding union banners and flags – and dissuaded or prevented workers from entering.

The industry watchdog also claims that McDonald, the union's assistant secretary in WA, swore and verbally abused a female supervisor when she crossed the picket line with her staff.

It is alleged McDonald told the supervisor's staff they were being bossed around by a woman, before threatening employees that they would not work in Perth again if they crossed the picket line.

“Coercion has no place on Australian building sites,” FWBC director Nigel Hadgkiss said when speaking about the case.

“Unions should seek to exercise their lawful rights, rather than resort to using coercion and industrial tactics that hinder the construction of Australia’s infrastructure.”