Make ministers accountable for leak: Labor

Bill Shorten has written to Malcolm Turnbull asking that senior ministers are held to account for any role they played in the major cabinet leak.

Labor wants the investigation into how hundreds of top-secret documents ended up in a filing cabinet at a Canberra second-hand shop to be wide-reaching and followed up by a comprehensive overhaul.

"The end result cannot be simply to slate blame to a middle-ranking or departmental officer deemed to be expendable," Mr Shorten wrote in the letter to the prime minister on Wednesday.