A senior Victoria Police officer has pleaded guilty to 10 fraud offences, including dishonestly obtaining six properties and rorting Centrelink, following a major investigation by the state's corruption watchdog.

Sergeant Rosa Catherine Rossi, 57, also pleaded guilty in the Melbourne Magistrates Court to unauthorised access of the police database, LEAP, and falsely claiming in statutory declarations that her name was Dianne Marshall and she lived in Endeavour Hills.

Sergeant Rosa Rossi in 2016 Credit:Damjan Janevski

The Age can reveal that Rossi used a string of aliases over the past 20 years, including Nora Marguglio, Rosa Spencer and Bella Rossi.

In 2005, she declared bankruptcy under her former name Rossa Catherine Marguglio, owing more than $750,000 to several banks and racking up massive debts on several different credit cards.