Queensland police are investigating whether the CFMEU is involved in the assault of a Cross River Rail worker outside his home.

The man was walking to his car about to head to work on Wednesday morning when he was set upon from behind by two masked attackers armed with a metal pole.

Nine News can confirm the worker being assaulted is Fou Ah-Lam, who was filmed trying to cross a CFMEU picket line to go to work in May.

That incident devolved into a violent brawl between striking CFMEU members and non-union workers.

Police investigating this week’s attack were doorknocking neighbours last night.

Ah-Lam told police he believed the two men were members of the CFMEU and attacked him in retaliation for crossing the picket line.

Premier Steven Miles is now talking tough on taking action against the union.

“What changed yesterday is this clear allegation of violent behaviour by the CFMEU in retaliation against another worker,” he said.

The CFMEU denied it had anything to do with the attack.

“It is outrageous that [Cross River Rail contractor] CPB has linked the CFMEU to an alleged assault on a Cross River Rail worker,” CFMEU Queensland/Northern Territory secretary Michael Ravbar said.

“The CFMEU has no knowledge of, or involvement in, the alleged assault.”