More oil leaking from Rena

Debris being lifted out of the ocean from the Rena. PHOTO/SUPPLIED

Several pockets of oil have been found trapped inside the engine room and the remains of the accommodation block of the MV Rena wreckage this week.

Hugo Shanahan, a spokesman for the owners, confirmed to the Bay of Plenty Times seven pockets had been located and operations to recover them, at depths between 35 to 48 metres, would begin.

Mr Shanahan could not give a estimate on how much oil there was.

"They are diving at such significant depths, it's hard for them to give any accuracy [on the size of pockets or amount of oil] we will quantify the total amount of oil once we have recovered it, that is the most accurate way to do it," he said.

Mr Shanahan said there had been a sheen on the ocean right next to the Resolve 1000 barge on Thursday.

"When it [the oil] escapes it is little droplets which rise to the surface of water from significant depths. When it hits the surface, it disperses very quickly and because of the very little quantity, it then evaporates.

"Attempts to date to try and recover anything have been difficult because of how the process happens so quickly but they have been working to locate the source and they have now found these pockets. They believe with the right planning they can release them and trap them as they come to the surface."

Mr Shanahan said although planning was underway to recover the oil he could not give a specific date on when it would be.

"It could be a couple of days or a couple of weeks."

"Significant progress" had been made in the recovery on the debris field to date, he said.

3,344 tonnes of debris so far had been recovered.

Roger King of TMC said the diving operation was purposefully undertaken in response to sheens of oil surfacing during ongoing clean-up operations at the site, which was difficult to recover due to the small and periodic quantities escaping.

"Bay of Plenty Regional Council and Maritime New Zealand representatives have been briefed of the situation including a light sheen on Thursday - both authorities are supportive of the action being taken."

"While the accumulation and gradual release of small quantities of residual oil over time has been expected, the overall quantity that remains is believed to be less than a tonne. We won't know the amount we are dealing with here until the recovery operation is completed," said Mr King.

"To have located the source is a positive development - the owner's insurer has now instructed plans for the oils' removal in a safe and responsible manner. The depths divers will be working at will require further careful planning, as well as to ensure we have adequate spill response resources in place during the operation," he said.