About 5000 square metres of reef has been damaged by HMNZS Manawanui as it went down in a marine reserve off the southern coast of Samoa.
The vessel ran aground and later sank at the weekend.
Clean up and salvage operations are underway as debris continues to come loose from the vessel.
Three shipping containers floating in the sea near the sunken Manawanui ship. Photo: RNZ / Louise Ternouth
Three cargo containers are among the contents to come away - two are floating in the sea with one now stuck on the reef.
The 950 tonnes of fuel inside the vessel is still contained.
RNZ reporter Louise Ternouth is on Samoa's southern coast and has been out on the water with the defence force today.
"We set out this morning in very windy and treacherous conditions out on the reef," she told Checkpoint.
The team waited until it was safe to get out on the water.
"Before we were even told we had reached where the vessel was - which took up to an hour to get out there - you could smell it, you could smell the pungent petrol fumes and we knew we were in the right spot.
The Manawanui sinks on Sunday morning. Photo: Supplied / Profile Boats
"We also saw an oil slick on the water which the New Zealand Defence Force maintains is residual fuel from the initial sinking.
"We could also see a bit of debris in the water but the main thing that stood out was the three shipping containers that were floating."
The containers appeared to be mostly empty, Ternouth said.
"One of those, though, was stuck on the reef, which will likely become a problem in the future, I imagine, to retrieve."
Navy diver Sam King. Photo: RNZ / Louise Ternouth
A diver tasked with inspecting the HMNZS Manawanui said his team could not see any signs of further oil leaking from the sunken ship.
The ship is 30 metres down, and diver Sam King said it was surreal to see it in a clean condition but lying on its side on the sea floor.
"The ship looks like it's sitting on a kind of flat rock bed, so luckily from what I could see at least it is not sitting on top of coral, which is lucky."
There is about 10 metres of visibility underwater, King said.
"You can see quite a bit from where you are just diving around the ship.
"We couldn't see any oil spilling out while we were down there."
A team of divers filmed and photographed the ship and located the voyage data recorder - the equivalent of an aeroplane's flight recorder.
"(It's) an important piece of equipment on a ship which records a lot of things that go on. ... And again that will be used as an important tool for the investigation which is ongoing."
After assessing the wreck's initial condition the team will be looking ahead at what is next in the salvage operation.
"One of the other divers managed to bring up the name plaque of the ship, which is quite a significant thing.
"So going forward I think that will be a big part of history. It's something special that we were able to bring back from the ship that I think will mean a lot to people, hopefully."
Outside Sena Lei resort where the NZDF was stationed today. Photo: RNZ / Louise Ternouth
Lieutenant Christian Lloyd with the navy's search dive team said hazards need to be identified before fuel was extracted from the Manawanui.
"The primary task is to identify potential hazards or further hazards that can occur environmentally and also getting our initial assessments of the damage.
"This will be able to provide an accurate picture back to the Samoan government and also New Zealand as a whole.
"At the moment the ship is stable on bottom, it's safe to dive, so that gets us a really good opportunity to get a clear picture."
Marine consultant John Riding said the Manawanui's position on the sea floor could make it easier to extract the 950 tonnes of fuel that remained on board.
Riding said the diesel fuel was light enough to be pumped from the ship once salvage crews breached the hull.
"There are salvage techniques which would basically allow and organisation to remotely drill into the side of the hull and it's fairly easy at 30 metres depth to extract the fuel - because the vessels lying on it's side - you don't have to start drilling down through super structure to get at the fuel tanks which are mostly lying at the bottom of the ship," Riding said.
Riding said the Manawanui's construction to commercial standards may have affected the ship's chance of staying afloat after it ran aground.
"It would be, what I would call, a one compartment standard that means if one compartment gets flooded she can stay afloat but if a second one starts to get flooded she will sink. If vessels are dedicated survey vessels they are sometimes built to the same standard as passenger vessels which can have two compartments flooded if they get into grounding trouble," Riding said.
Riding said raising the ship was is likely to cost tens of millions of dollars.
"Commercial [vessels] all carry third party and liability insurance which is provided by protection and indemnity clubs (P&I clubs). The protection and indemnity clubs pay wreck removal which can get very expensive and P&I clubs are international bodies, generally non-profit making and they have deep pockets. It means - in a commercial sense - there would be a lot more funding readily available to address wreck removal etc.
"Of course little old New Zealand we've only got a small defence force in the big picture and there's only so much we can afford to spend on Navy vessel. Navy vessels are likely to have third party liability - just the same as a car - but are unlikely to have the type of cover a P&I club would provide," Riding said.
