The Construction, Forestry, Mining and Energy Union and six of its officials have been fined more than $21,200 for illegally blockading a Perth airport expansion site in late 2013.
The union organised a protest at the site of the $80 million project on October 22, 2013 over what it said was more than $150,000 in unpaid wages involving 46 workers.
About 100 protesters and CFMEU officials blocked 150 other employees from accessing the site for three and a half hours, and threatened the airport and head contractors, Leighton Holdings-owned Broad Construction, with returning to disrupt the site the next day until the workers were paid.
Concealed Interiors, a wall and ceiling company which had been subcontracted by Broad Construction, was the employer responsible for the unpaid wages, with some workers owed $10,000.
The workers were ultimately paid.
The Federal Court imposed fines of $21,225 for breaches of the Fair Work Act.
The officials fined included current state secretary Mick Buchan and assistant secretary Joe McDonald.
Fair Work Building and Construction director Nigel Hadgkiss said the CFMEU had ignored lawful dispute resolution avenues.
The airport's expansion continues to be plagued by financial problems in 2016, with reports of delays and cost blowouts, dozens of subcontractors not paid and a lawsuit by builders Built Environs against the Perth Airport Authority.