The construction union is facing court over allegations of offensive behaviour at Queensland's $5.4 billion Cross River Rail project after an organiser allegedly asked the site's male safety official if he wanted to see his penis because "there's enough to go round".

The Australian Building and Construction Commission launched Federal Circuit Court action on Monday against three Construction, Forestry, Maritime, Mining and Energy Union organisers for "aggressive and highly offensive behaviour" on the massive infrastructure project, accusing them of unlawfully entering the site, filming staff without permission and ignoring safety inductions.