Former construction union boss John Setka has been referred to police after he gained access to two government building sites to speak to workers.

Victorian Premier Jacinta Allan said she had referred the ex-CFMEU boss to Victoria Police after he spoke to about 700 workers at a Metro Tunnel project site on Thursday morning.

It comes after Setka spoke to workers at the new $1.5 billion Footscray Hospital, in Melbourne’s inner-west, on Wednesday.

“There is no place for John Setka on these worksites,” Allan said.

“He was on the sites unlawfully and that is why the matter has been referred to Victoria Police for their further investigation.

“In terms of who attends worksites, there are well-established processes here and it is the government’s expectation that those building industry companies manage this process appropriately, which is clearly not what happened in these incidents over the past 24 hours.”

Setka launched into an expletive-laden criticism of the state and federal governments during his visit to the hospital site.

“People sort of asked why I resigned and I’m going to be honest with youse, f—ing Albo, and his f—ing bullshit,” he told workers.

Setka, who quit in July after allegation bikies and underworld figures had infiltrated the union, gave insight into what led to his resignation.

“They want a scalp – you tell them ‘I’ll go, I’ll resign right now, I’ll resign tonight’,” he said.

“My job is to protect the union and its members. I’m going to be gone in a few months.”

The Victorian government has asked construction giant Multiplex, which is managing the project, how the on-site rally unfolded.

The Fair Work Ombudsman said it was investigating allegations former CFMEU officials have been on construction sites. It encouraged those with information to come forward.

Victoria Police has been contacted for a response.

Federal Opposition Leader Peter Dutton said Setka had “stunning audacity” to enter a second worksite.

‘John Setka’s worked out as well that Anthony Albanese is a weak leader,” Dutton said in Sydney.

“[The CFMEU] trade in misery. They go onto building sites, which forces up the cost of building.”

Meanwhile, unions are banding together to support a High Court challenge after the CFMEU was placed into administration.

The Maritime Union of Australia will join other trade unions to help fund the CFMEU’s legal battle, claiming the federal government’s decision was “unjustified, chaotic and reckless”.

It could jeopardise progress on enterprise bargaining agreements, send a green light to “bad and abusive employers” or set a precedent for moves against other unions based on “untested media allegations”, the maritime workers’ group warned.

“We are supporting … and backing them in as they fight for the right of their division to exist,” the MUA said.

“We are also concerned by the near certainty that similar future legislation will be used by governments of either stripe against other militant blue-collar unions, including the MUA.

“We have been on the receiving end of these calculated political and media smears in the past and will support our fellow members … as they seek to clear their names and fight for the principles of natural justice, presumption of innocence, the rules of evidence and procedural fairness.”

The embattled CFMEU had its construction and general divisions placed into administration after the corruption allegations prompted the federal government to try to rein it in.

Laws that passed parliament in August gave the relevant minister powers to intervene and slap life bans on CFMEU officials.

Mark Irving KC was appointed as administrator and more than 200 elected CFMEU officers had their roles terminated immediately.

-AAP