Ninety of the ship's containers have fallen off the deck .. with debris washing on the once-pristine shores.
In what is being described as New Zealand's worst environmental disaster, the 47,000 tonne Rena has already leaked about 350 tonnes of oil into the sea.
There are now fears the vessel could break up, after massive fissures appeared in its hull after being pounded by rough weather.
Reporter: Bronwyn Herbert
Speakers: Bruce Anderson, salvage unit manager, Maritime New Zealand; John Key, prime minister of New Zealand; Diamantis Manos, managing director of shipping company Costamare; Patrick Quirk, general manager, Maritime Safety Queensland
HERBERT: High tide has painted beaches of the Bay of Plenty black with oil.
Added to that, contents of large containers have washed up and now hundreds of hamburger patties replace sea shells along the shore.
WOMAN: It's quite heartbreaking really, especially when I've seen the seagulls all dying.
WOMAN 2: It almost makes you want to cry, because I've got two weeks holiday at the moment, I teacher aid. I had ideas of like coming down to the beach and sunbathing and swimming.
YOUNG BOY: Yeah well it kind of destroys your holiday. The fun part about a holiday is you come down the beach and swim, not see oil and foam all over the beach.
HERBERT: Fears remain the vessel could break in two and spew more oil into the ocean.
Maritime New Zealand has confirmed one of the containers houses the hazardous chemical alkyl sulfonic acid, but that container hasn't yet been located.
Bruce Anderson is the salvage unit manager with Maritime New Zealand.
ANDERSON: It's quite hard to identify which container is which when it's in the water. But that's another reason why the public shouldn't go anywhere near those containers. They should just leave them alone and leave them for some specialists to deal with.
HERBERT: New Zealand's prime minister John Key says he's only too aware of how this oil spill could hurt tourism, for a country still mourning from the Pike River Mine disaster and the Christchurch earthquake.
KEY: As minister of tourism and as prime minister, we attract an awful lot of tourists to New Zealand because we have such a clean and green environment. On the other side of the coin, we're a country surrounded by coastline, we take the bulk of our goods via ships and for reasons that we can't explain at the moment, there's been a terrible accident in New Zealand. And I think people will understand that these things can happen.
HERBERT: Fears remain the vessel could break in two and spew more oil into the ocean, though Maritime New Zealand says the big crack in the ship's hull doesn't appear to have gotten worse.
Though the size of the problem for Costamare, the company that owns the ship, is growing.
For the first time since the Rena crashed, its managing director Diamantis Manos has spoken publicly.
He issued this statement by video release late today.
MANOS: Obviously something went very wrong, and we will corporate with the Transport Accident Investigation Commission of New Zealand, TAIC, to find answer.
However, to the people of Tauranga, we want to say that we are deeply sorry for the situation that has arisen and the threat you are now facing from fuel oil from the vessel washing up on the beaches on your beautiful part of the world.
HERBERT: Australian teams have also pitched in to assist.
Patrick Quirk is the general manager of Maritime Safety Queensland.
QUIRK: We've been through similar occasions in our recent past, Shen Neng, Pacific Adventurer, particularly on Morton Island and the Sunshine Coast beaches.
The Australian Maritime Safety Authority, who's our national agency on these matters, asked for assistance last weekend and we've certainly provided a number of staff who are currently in New Zealand. We have some flying over today and we have another tranche of people gearing up to go early next week.
HERBERT: Already 88 containers have fallen from the ship, how concerning is it?
QUIRK: Well I think New Zealand's got a double problem there. Our instances in Queensland have primarily been issues of ship incidents, salvage and oil pollution. New Zealanders are facing the fourth tranche of a container ship with, what, 2,500, 3,000 containers on board, some of them containing hazardous material. They are facing a major problem.
From what I can see, from what I understand talking to people over there, since day one, anything that could go wrong has gone wrong with that incident. But we can understand the dramas they're going through over there but there is no magic wand, there is no silver bullet. Once that oil is in the water, it's a long process to clean up.
HERBERT: So the key is in making sure less oil ends up in the ocean?
QUIRK: Well I think the way the vessel's cracking I think they'll be sort of lucky to manage how much comes out; I think that sort of time has passed. The issue is now is how they're going to confront the oil that's in the water and what could possible come ashore on the beaches.
HERBERT: Meanwhile the navigator of the Rena has appeared in the Tauranga District Court facing charges in relation to his role in the grounding of the ship.
It follows a similar appearance by his captain in the same court yesterday.