Twenty people have been arrested following a major investigation that has spanned nearly a year into alleged corruption within several prisons.

Detective Inspector Colin Parmenter, of the National Organised Crime Group, said on Thursday police began investigating criminal activity at the Mt Eden Corrections Facility (MECF) in July 2025.

This week, 20 people were arrested in relation to the investigation, dubbed Operation Jasper.

"Those arrested include Corrections officers, reintegration officers and members of the public associated to prisoners.

"Police have identified serious criminal offending, so serious that the corruption and bribery charges required the attorney-general's consent to prosecute."