Authorities now accept the Rena will break up, saying it's only a matter of time.
Maritime New Zealand (MNZ) revealed today there are cracks in the hull and a ONE News chopper also sighted the cracks today.
The front of the ship is wedged into Astrolabe Reef off the coast of Tauranga and the ship's back is hanging over much deeper water.
Swells up to five metres are lifting and dropping the vessel, sending it to breaking point.
MNZ says the Rena's bow is still stuck fast on rocks, but the stern is being swung about by huge swells, putting stress on the ship's structure.
MNZ advisor Captain John Walker, who was one of the last people evacuated off the vessel last night, said there is a fold on the port side and the cracks on the vessel "are getting worse".
"The ship won't be salvaged as a ship because very soon it will be broken in two," Walker said.
Authorities say the challenge is to stop the back half sinking.
Their plan is to attach a tugboat to the back of the boat to try to hold that section to the reef. And if that fails, they will attempt to tow it to shallower water before it sinks.
Prime Minister John Key said it is quite clear that there has been continued deterioration to the Rena.
"She has been some structural damage which is quite apparent to everyone to see," Key said.
"That's presenting a series of different challenges as we go through this recovery effort, and everyone's acutely aware of the environmental risks if there is a break up to the ship."
Key said everyone is working a huge number of hours to try to resolve this situation as quickly as possible
"No one should underestimate the significance of the challenges we will face."
Have you got photos or video of the oil slick today? Send them to firstname.lastname@example.org
The ship, which struck the reef last Wednesday, has leaked more than 300 tonnes of oil into the sea off the coast of Tauranga.
Oil has washed ashore in Tauranga Harbour today and containers have washed up on Motiti Island.
Oil was reported on the shore in Kulim Park this morning and there were also reports of oil at Sulphur Point and along the foreshore at Matua.
The Prime Minister's pledged the Government's commitment to restoring oil-spattered beaches to their former glory.
His first stop was to the tiny town of Maketu today where locals are frustrated.
Residents told ONE News there is a lack of official help with the clean-up.
The sandy shores cleaned just yesterday now resemble a toxic wasteland as far as the eye can see.
"I'm seriously pissed off like seriously there's a lot of really angry people here and they've got no gear to take the containers off the boat," one resident told ONE News.
"There's nothing in New Zealand that can take them off so they knew right from the start it was going to break up and fall to bits."
Meanwhile, soldiers from the Defence Force begun clean up work at Papamoa today.
The group of 80 soldiers are operating from Harrisons Carpark, 2.5 km north of the Papamoa Surf Club and it is expected that by this afternoon there will be more than 150 soldiers working on the beaches.
"We're here purely to clean up it's being co-ordinated by Maritime New Zealand and we're just muscle on the ground picking up oil off the beach," a soldier said.
Masks could be issued to residents along the shore because of the strong stench from the oil.
Many are struggling to even identify the wildlife washed up in the slick.
"There's more oil on the beach and you can smell the fumes as you enter," Al Fleming from Forest and Bird said.
"It's heart-wrenching, this is a terrible time of year for this to happen for our wildlife."
He said there are birds feeding at sea and also whales and seals that will be in local waters that will be affected by the spill.
If you see any oiled wildlife report it to Forest & Bird at 0800 333 771
Do you have cargo on the Rena? Contact ONE News email@example.com