A naval training base in Victoria is in lockdown after suspected hazardous material was found in a naval officer's room.
Police say a man has been arrested after a "number of items" were located at a residential unit at the HMAS Cerberus navy base near Hastings on the Mornington Peninsula.
Superintendent Neil Paterson said police were called about 11am after the potentially hazardous material was found in the room of a 30-year-old able seaman.
The man is assisting police with their inquiries, and Superintendent Paterson said the material would be tested, but it did not appear to be explosive.
"It's not a large quantity of material but the materials are hazardous and they are not normally found on barracks," Superintendent Paterson said.
A 400-metre exclusion zone has been set up around the unit.
The bomb response unit and members from the arson and explosives squad are at the scene.
There is no suggestion the man intended to use the material for any attack, and no links to terrorism, Superintendent Paterson said.
There was no immediate threat because of the material, but it was unclear whether the man had tried to hide the items.
Superintendent Paterson said the concern was that different materials were found together.
"It's unusual to find these particular materials, together, on barracks."
A defence force member is on scene assisting police with the investigation, a defence department spokesman said.
"A routine inspection this morning of on-base accommodation in HMAS Cerberus has resulted in hazardous material being located in a residential unit," he said in a statement.
"As a precaution, a 400-metre safety zone has been established around the accommodation block."
Paramedics have not been called to the scene or put on stand-by over the incident, an Ambulance Victoria spokesman said.