The stricken cargo ship Rena has split in two but remains firmly wedged on the Astrolabe Reef off the coast Tauranga.
Maritime New Zealand today said a gaping crack in the ship's hull had widened in swells of up to 5m on Saturday.
The vessel may still be joined together under the surface and divers would investigate as the weather permitted.
A spokeswoman this afternoon said there was no change to the ship's state today, and it remained firmly wedged on the reef, where it ran aground early October.
Light oil sheens were seen coming from the bow and stern of the ship this morning, with an unknown quantity of oil still on board.
Two containers are confirmed to have fallen overboard on Saturday while a further nine have been "misplaced''.
These could have been crushed in the hold or fallen overboard.
Four oiled blue penguins were collected in the past two days, which would be sent to the wildlife recovery centre later this week.
One oiled blue penguin was found dead.
One dotterel, two grey faced petrels and 17 penguins are in care at the Massey facility in Palmerston North.
Winds of between 10 and 20 knots and swells of 1-2m hit the Bay of Plenty this morning, with possible thunderstorms forecast until midnight.
The bad weather has put a halt to container removal operations.