Rena recovery authorities have confirmed oil sheens spotted near Astrolabe Reef last year came from the wreck.
The latest report on the project released yesterday also says the wreck has moved into deeper waters.
The oil sheens, first reported in December, prompted salvors Resolve Salvage and Fire to recover 992 litres of oil trapped within and near the substantially degraded engine room.
"This operation was in response to intermittent oil sheens being observed on the surface during debris clearance operations.
"The divers were first tasked with locating the source of the sheens and then with recovering the pockets of oil that could safely be recovered. These efforts have further reduced the minor oil quantities remaining within the structure," the report says. Resolve, which had been the leading salvage team working on Rena since August 2012, had now finished its work at the wreck.
Efforts to remove the remaining debris from the wreck were now being performed by New Zealand Diving & Salvage.
Its team of divers was tasked with removing any remaining hazards to divers and recovering inorganic materials and aluminium ingots to a depth of 30m.
The team had already recovered 43.3 tonnes of debris.
New Zealand Diving & Salvage was expected to continue to remove any identified deposits of copper where recoverable, using specialist underwater suction equipment.
It would also undertake more investigations if any further oil sheens were reported and, if safe, remove the oil at its source.
The project report also includes images illustrating the wreck's aft section on the sea floor, showing how it had continued to deteriorate and move into deeper water over time.
A survey was carried out following Cyclone Pam by ADUS DeepOcean surveyors between March 18 and March 23.
The sequence of movements had been forecast by naval architects appointed by the insurers, the report says.
