The construction union has been fined $1.5m and its senior officials another $190,000 over unlawful strikes at the Barangaroo South site in Sydney.

The full federal court imposed the penalties on Friday – a record for proceedings brought by the government’s building regulator – after 1000 workers walked off the job in July 2014.

Despite the Fair Work Commission ordering them back to work, about 300 workers did not return the following day.

The strike action was triggered after a delegate for the Construction, Forestry, Maritime, Mining and Energy Union (CFMMEU) was suspended from work after he and a site manager clashed physically over safety issues.

The delegate raised concerns over a walkway at one of the International Towers Sydney, a trio of commercial skyscrapers in the now-revitalised district.

A previous judgment had found that during the two-day strike, union official Luke Collier said words to the effect of “you’re lower than a paedophile, you grub” to a government inspector.

The same official also read out the inspector’s mobile phone number at a workers’ meeting.

A judge said the union had long demonstrated it paid “but little regard to compliance with the law and indeed has repeatedly sought to place itself above the law”.

The full court observed that the union had a substantial contravening history before fining it $1m and its NSW body $510,000.

Four union officials including Collier were fined more than $40,000 each and another five officials were fined $21,000 in total.

The Australian Building and Construction commissioner, Stephen McBurney, said the level of abuse and intimidation directed against workers, public servants and police officers demonstrated “a complete disregard for the law”.