Two men have been charged and Victorian police have seized drugs, guns and cars linked to the Construction, Forestry and Maritime Employees Union (CFMEU) as part of an investigation into alleged corruption in the building industry.

On Monday, detectives from Taskforce Hawk arrested five men and searched six properties including the Victorian headquarters of the union, saying they were investigating secret commissions, fraud and drug trafficking.

Police said four CFMEU registered vehicles were seized, as well as 10 mobile phones, a Schedule 4 poison, .22 rifle and ammunition, laptops, documents, iPads and a number of USB storage devices.

No arrests were made at CFMEU headquarters, police said, and administrators for the union said none of its officials had been charged.

A 36-year-old from Chirnside Park was charged with possessing a Schedule 4 drug and bailed to appear at Ringwood magistrates court on 10 November, and a 46-year-old from Westbury was charged with failing to store a long-arm firearm and failing to store ammunition as required by the Firearms Act 1996.

He was bailed to appear at Latrobe Valley magistrates court on 11 January.

The other men were released pending further inquiries.

“The investigation in relation to the alleged secret commissions remains ongoing,” police said in a statement.

“A secret commission refers to corruptly giving, receiving or soliciting an undisclosed financial benefit, reward, payment or kickback.”

Operation Hawk was established in July 2024 to target criminal behaviour linked to the construction industry, and transitioned to Taskforce Hawk the following year.

This was in response to a number of fresh allegations of serious and violent criminal behaviour.

“Taskforce Hawk is focused on assessing new intelligence and evidence relating to allegations of criminal behaviour linked to the construction industry,” police said in a statement.

“It also continues to proactively target organised crime associated with the sector, including a focus on any individuals employed within the construction industry who have known links to outlaw motorcycle gangs.

“Police are also instigating approaches with relevant industry stakeholders to gather intelligence, as well as working closely with a range of law enforcement partners, regulators and government authorities.”

Det Acting Supt Jamie Walker, from the organised crime division, urged anyone with information, no matter how seemingly insignificant, to come forward.

“Criminal conduct, involving corruption, intimidation and violence within the construction industry is unacceptable,” he said.

“We will continue to target serious and organised crime entities and dismantle corrupt and criminal business activities in the construction industry.”

In a statement, the administrator of the CFMEU said the union was cooperating with police.

“Criminals and bad actors in construction remain a major threat to the workers which is why we need greater regulation and scrutiny across the sector,” CFMEU administrator Michael Crosby said.

“This administration has undertaken unprecedented reform and anyone associated with criminal elements will have absolutely no place in this union’s future.”

The scandal was a leading contributor to the ousting of former Victorian premier Jacinta Allan, who left her post last month.

The new premier, Ben Carroll, announced a royal commission last week.