A Victorian CFMEU organiser has been arrested while trying to enter Melbourne's Regional Rail Link work site.
A 33-year-old Preston man was arrested in McNabb Avenue, Footscray on Tuesday morning and is expected to be charged on summons with trespass, a Victoria Police spokeswoman said.
CFMEU national construction secretary Dave Noonan said the organiser went on site in response to a call from a member over a safety issue.
He said while the organiser had authorised right of entry, he was refused as he did not bring his papers to the site.
Mr Noonan said the incident was yet another example of Prime Minister Tony Abbott attacking workers' rights.
"It is clear that Abbott is attacking workers' rights and trying to prevent us from doing our job," Mr Noonan said.
"The organiser was well known to everyone on site. This heavy-handed treatment is way out of proportion."