A construction union has been ordered to pay almost $60,000 for threatening to inflict "Armageddon" if a site contractor in South Australia enforced a legal order

The Federal Court on Thursday fined the Construction, Forestry, Mining and Energy Union and two of its bosses $57,500 for intimidating the head contractor of the Royal Adelaide Hospital’s construction site.

He was threatened in 2013 not to enforce a Fair Work Commission order which required employees on the project not to take industrial action.

Former CFMEU assistant secretary Michael McDermott threatened to inflict “Armageddon” if the order was enforced, the court heard.

While SA state secretary Aaron Cartledge warned national industrial action would be brought against the contractor’s other projects.

Justice Anthony Besanko found the officials’ actions to be deliberate, and found the purpose of the threats was to coerce the contractor to not exercise their legal rights.

He also took into account the CFMEU’s “significant record of non-compliance” with workplace laws when handing down his verdict.

The Australian Building and Construction Commissioner Nigel Hadgkiss says the penalties against the CFMEU in South Australia are building.

“This decision means $1,126,600 in penalties have been imposed by the Federal Court against the CFMEU and its representatives for proven unlawful conduct that occurred across Adelaide in a nine-month period,” Mr Hadgkiss said.

“Unfortunately, the conduct we’ve seen in this case is not isolated, but instead reflects a widespread contempt for the rule of law that pervades the industry.”