The New Zealand Navy has confirmed it found three unexploded bombs in Vanuatu's Port Vila Harbour on an exploration mission earlier this year.
The Commanding Officer of the Operational Diving Team, Lieutenant Commander Trevor Leslie, says they could only do a specific survey of the area suggested to them by people with local knowledge.
Dive operators say there are at least six bombs in the harbour, and other ammunition from the Second World War.
Lieutenant Commander Leslie says bombs in the water can be very difficult to remove.
"A lot of the ordnance we are finding is still in a live or dangerous state but dealing with maritime ordnance one of the other things we have to consider are just the other dangerous aspects of diving in general and that's a real consideration for us. The items in Vanuatu Harbour are about 21 metres, that's relatively deep, so it's a real vast problem and it comes with lots of association risks as well."
Lieutenant Commander Leslie could not confirm whether there is a plan to remove the bombs.