Victoria police will inform the state’s anti-corruption watchdog that it did not comply with the law when it used wide-ranging powers to search people for weapons on 23 separate occasions dating back eight years.

The non-compliant searches resulted in 33 people being charged or fined, all of whom will be contacted by police and informed of the problem.

But potentially hundreds of people were searched without authorisation under the legal breaches, some of which were only uncovered after the police force was contacted by Guardian Australia.

Eighteen of the searches were uncovered during an internal audit police conducted of all designated areas declared between March 2017 and March 2025.

The audit has since been expanded after Guardian Australia asked the force about four areas that were designated since September.

Those four non-compliant operations, and a fifth, have since been uncovered, and the audit is continuing.

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Under the laws, police can search anyone who enters a designated area during a specified period of time, using either electronic wand or pat-down searches. Most of the searches are conducted under Operation Omni.

“Victoria Police is aware of issues, which mean a number of weapons search operations are likely to be non-compliant or partially non-compliant with legislative requirements,” a police spokesperson said.

“Most of these issues arise from administrative errors such as public notices not including the name of the event where the operation was held.”

The four breaches uncovered by Guardian Australia related to operations that were advertised on a Victoria police website, but not in the government gazette, as is legally required.

The designated areas which Guardian Australia asked about occurred before protests in the Melbourne CBD on 22 November, 15 November, 19 October and 13 September. The other searches that were non-compliant have not been released.

The 19 October protest resulted in violence that was condemned by police and the premier, Jacinta Allan, and also resulted in injuries to protesters when police deployed a stinger grenade.

These searches occurred under designated area laws that were only recently made more powerful.

Police said a small number of searches also occurred outside event hours, and that a number of operations conducted across numerous days weren’t connected to an event as was legally required.

However, not every search conducted during a non-compliant operation was affected, because police can still search people if they have a reasonable suspicion of wrongdoing.

“At this stage, 33 people who were either charged or fined are adversely impacted. This represents less than 1% of searches during all weapons operations,” police said.

“The community should be assured the overwhelming majority of the 200 weapons search operations conducted over the period remain valid, with no compliance issues whatsoever.

“Victoria Police is in the process of writing to the small number of impacted individuals and providing them with information about appealing any charges or seeking a review of any fines.”

Victoria police said the independent broad-based anti-corruption commission was also being notified, and that it had strengthened its processes.

It said the recent reforms would also “help avoid future issues”, and clarified that the recently announced six-month weapons search operation in the city was not affected.

But the compliance issues showed police should not have been given the increased powers, said Ilo Diaz, from the Centre Against Racial Profiling.

“These invalid designated areas shows that we cannot trust Victoria Police with these powers. There are not enough guardrails on the increasing powers police holds,” Diaz said.

“If these designated areas remain unchallenged, it will be communities of colour who will be impacted most. Unfettered power needs to be held to account, and this shows that if it wasn’t for people looking through the government gazette, this would never have been picked up.”