Australian troops will be training on Sydney waterways all week.
The Australian Defence Force said the training will held around Sydney Harbour, Middle Harbour, Manly Beach, Mosman Bay and surrounding coastal waters from Monday through to Friday.
Defence said in a statement the training would involve canoes and powered watercraft. Personnel would be in uniform and carrying training weapons.
AAP reports the training weapons are red and cannot be fired.
"Residents should not be alarmed if they notice an increased movement of vehicles, military personnel and watercraft in these areas as this is part of the training," the ADF said.