An official from the nation’s biggest building union who allegedly called a government employee a ‘f***ing piece of sh*t’ is facing court.

In a statement, Fair Work Building and Construction says it has taken Federal Court action against Victorian union official John Perkovic and nine other officials of the Construction, Forestry, Mining and Energy Union (CFMEU) as well as the union itself over allegations surrounding a spate of illegal entries onto Adelaide building sites earlier this year.

The regulator has alleged that Perkovic verbally abused one of its investigators at the Ibis Hotel project site in Adelaide after he and other union officials illegally entered the site.

FWBC says the union official used words to the effect of: ‘You are just about having a heart attack. You’re sh*tting yellow, you piece of sh*t! Go f**k… Brush your teeth next time you piece of sh*t, alright?’.

The regulator also says Perkovic pushed the official with his stomach, causing him to lose balance.

It is believed Perkovic was one of a number of CFMEU officials who flew into Adelaide from New South Wales/ACT, Victoria and the Northern Territory and created problems at three sites.

Along with the Ibis site, these included an aged care development in Kensinton Road, Leabrook, and Stage 1 of the Minda Homes Master Plan in Somerton Park, which will provide accommodation and services to people with intellectual disabilities.

The officials are alleged to have refused to show Right of Entry permits or provide 24 hours’ notice prior to entry, and refused to wear safety glasses when asked.

One allegedly told a manager to ‘f**k off’ and ‘Grow some balls’ when asked to show his permit at the Ibis Hotel site.

FWBC Director Nigel Hadgkiss hit out at the union’s conduct.

“The FWBC had to fly in extra Investigators to Australia’s city of churches to support the South Australian team during this spate of activity,” Hadgkiss said.

“FWBC takes attacks on government officials very seriously. Nobody should ever be abused, especially in the course of going about their job.”

Maximum penalties in this case are $10,200 for individuals and $51,000 for corporations.

The latest developments come as the union continued its long running criticism of building giant Grocon.

On Monday, the union said the replacement of sub-standard glass at the 150 Collins Street building in Melbourne would cost around $18,000.

Supplied by China Southern Glass, the glass had been subject to imperfections that could be seen from the street.