Victoria's Office of Police Integrity (OPI) has confirmed sensitive documents were found at the home of a former employee during a drug raid in Melbourne's northern suburbs.
Classified documents from other security agencies including ASIO and the Western Australia Police were also found at the house.
The raid took place earlier this month and an investigation is now underway into the discovery files.
In a statement, the OPI said the documents were linked to a former employee and the other files were from the employee's previous workplaces.
The OPI said it was cooperating with a police investigation and it had undertaken a full security and risk assessment which had so far found no compromise to any if its operations.
The secretary of the Victorian Police Association Senior Sergeant Greg Davies says the security breach is concerning.
"It is not the first time that files under the control of the OPI have found their way into supposedly the wrong hands," he said.
"Now if we have ASIO files being bandied about, certainly there would be concerns from that agency in relation to national security."
He says the Police Association has always believed that there needs to be a broad-based anti-corruption commission in Victoria.
"We're faced with the ludicrous situation of the police force having to investigate the body set up to ensure the police force has independent oversight," he said.
"It's quite a bizarre situation."
