Boat sinks in Darwin Harbour, leaks oil

A boat has sunk in Darwin Harbour and divers are working to plug a leak that is spilling oil.

No one was on board the recreational vessel, approximately 14m long, when it started to sink about 8am on Wednesday.

The boat is now sitting at the bottom of the ocean six metres deep and absorbent booms have been deployed to help contain leaking fuel oil.

A dive team is working to plug the leak at the source, assess damage to the hull and advise on potential salvage operations.

The owner says there's about 40 litres of diesel fuel on board the ex-navy dive tender vessel.

Regional Harbourmaster Tony O'Malley said there were no reports of wildlife being harmed.

"Priority one is to prevent any environmental harm," he told ABC Radio.

"Thankfully it's diesel fuel so it's not too bad. Diesel evaporates relatively quickly."