RAN in Papua New Guinea:
The Royal Australian Navy is investigating an uncharted wreck, believed to be a submarine, which was found during the conduct of Operation RENDER SAFE 2011 off Rabaul in Papua New Guinea, on 26 October 2011.
The wreck was discovered in a joint activity by the New Zealand Navy survey ship HMNZS Resolution and the Australian Minehunter HMAS Gascoyne.
The wreck is located in Simpson Harbour, which was an area known for submarine operations during World War II.
As with any wreck discoveries, immediate identification is not possible and work will continue over the coming days to identify both the type and the nationality of the vessel.
Once further details are ascertained, the relevant country authorities will be advised.
Authorities from the USA, Japan, PNG and New Zealand have been informed of the discovery
Operation RENDER SAFE is the Australian Defence Force (ADF) contribution to enduring explosive ordnance disposal (EOD) support to the nations of the south-west Pacific, being conducted over the period 18 October to 4 November.
UPDATE: It appears that the sub is Japanese.