Cargo vessel Rena ground to a halt on Astrolabe Reef last week, and oil leaking from the cracking ship has killed nearly 1000 birds and contaminated beaches.
Seven salvors and two industrial chemists were helicoptered on to the ship today, but could not start pumping the estimated 1,346 tonnes of oil on board the vessel.
Maritime New Zealand (MNZ) salvage head Bruce Anderson said workers have been able to open the first man-hole to a fuel tank and were testing to see if it was safe to enter on the unstable ship.
"The stern is in a precarious situation. It's not quite as stable as we once thought."
Divers have been inspecting the port and starboard side of the vessel over the last two days, he said.
"The message that they're sending back to us is that the vessel is sitting with a portion of it still in space, so it's not as stable as we had hoped."
He said if the weather turned, there was a chance 100 tonnes of oil in the duct keel could leak out.
Mr Anderson said a salvage expert deemed the ship one of the worst wreck he'd ever seen.
"This thing was grinding and groaning away as the vessel was twisting and mashing parts of it up. He was saying it's one of the scariest he's seen."
MNZ scene commander Nick Quinn said the oil extraction process would be in "difficult and potentially hazardous conditions," as the ship is still on a 21 degree list.
Four platforms had been attached to the side of the ship to hold welders, power packs, generators and machinery to complete the oil extraction.
An Archimedes screw pump will be inserted into the tank to extract the oil hardened to a consistency of "marmite", he said.
The salvors were to be helicoptered off the boat today and would try to return tomorrow, he said.
MNZ scene commander Nick Quinn said the search for missing containers widened today. Approximately 44 of the 88 missing containers had been found, he said.
The team the team today searched a wider area to try and locate floating or sunken containers.
He said there was still a possibility of more containers falling off the boat, as it is still on a 21 degree listing.
MNZ salvage head Bruce Anderson said hazardous containers had been identified as being on the ship.
It's been a sunny day interspersed with showers in the Mount, and dozens of walkers, runners and observers are in the area for the start of the weekend.
Beach access remains restricted from Mt Maunganui to Maketu, and will remain in place until it is reassessed on Monday.
While clean-up efforts are underway at oil-stricken areas across coastal beaches, at the Mt Maunganui beaches it appears business as usual.
Dozens of rubberneckers have lined the coastal dunes with binoculars to try and glimpse the helicopters and vessels surrounding the stuck cargo ship, and a handful take their chances by heading on to the restricted beaches.
A few determined locals even braved the authorities to scoop remaining oil into plastic bags this morning, said one local.
Environment minister Nick Smith met with local iwi, tourism operators today.
"The situation has improved substantially, but we're not out of the woods yet."
He said the Government was working with the Chamber of Commerce on a potential support package.
