A former police officer has been charged with the leak of thousands of pages of Victoria Police documents to criminal organisations.

Police lost 1,600 files including 6,000 pages of information and electronic data in May last year in what was described as one the the most significant leaks in the history of the organisation.

The officer, who resigned during the course of the investigation, has been charged with perverting the course of justice, drug, property and gun offences.

Another five officers have been suspended on allegations of stealing from an inner city police station or stealing from drug addicts.

Victoria Police Chief Commissioner Ken Lay said they were extremely lucky no police informants were hurt as a result of the leaks.

"There was a very, very real risk some people may have been assaulted or worse as a result of this security leak, but we probably got it early enough to prevent that happening," he said.

"If this person had been able to stay in the Victoria Police, continue to access information, continue to provide this information to people with very significant criminal backgrounds there was potential for disaster."

He indicated more charges are likely.

The documents were found at three properties, including one which was linked to an outlaw motorcycle gang.