About 70 of Rena's containers have fallen off in wild weather overnight and the captain has been arrested and charged.
He will appear in court this morning.
A Martime New Zealand spokesman told the Bay of Plenty Times that news containers had fallen off Rena was confirmed to them this morning by crew on the naval ship Endeavour.
"We know that about 70 containers have fallen off. These came off the rear starboard side, which means the containers on the port side of the ship are unstable.
"Shipping is being re-routed around the area because of containers afloat in the water."
The spokesman said they would be taking a flight as soon as possible to view the situation but stormy weather was getting in the way.<inline type="video" id="12116" align="normal"/>
He said it was unknown at this stage if any of the containers that went overboard contained the hazardous substance ferrosilicon.
The shipwreck of the Rena has become New Zealand's worst maritime environmental disaster with the Government saying it will require a marathon effort to clean the oil off the Bay's beaches.
Up to 350 tonnes of oil spewed out when the Rena shifted its position on Astrolabe Reef in heavy seas early yesterday - five times larger than the total amount previously discharged since the container ship grounded last Wednesday.
"The environmental situation will be significantly worse," the Environment Minister Nick Smith told a press conference yesterday.
But only a few hours after Maritime New Zealand was telling the country that Rena had substantially righted itself on the reef, the news broke last night that the list had worsened to about 15 degrees starboard - a 10-degree lurch from Monday night when the ship seemed to nearly right itself from an 11 degree list.
The latest movement on the reef occurred in a four to five metre swell, indicating the heavy seas since Monday were making the situation with the ship much more fluid.
And with no one left on board until the big seas had settled down, officials announced yesterday they were unsure if the loose oil in the hull was still escaping and whether the shifting of the ship had caused further damage to fuel tanks.
Mr Smith said the clean-up would be more of a marathon than a sprint, calling it New Zealand's biggest maritime environmental disaster.
"It will be a long haul and all the indications were that it would be a matter of weeks."
He was joined by Transport Minister Stephen Joyce in painting a gloomy picture of what lay ahead.
Mr Joyce said there would be a "very considerable" amount of oil on the beaches over the next few days. Globs of oil were now washing up as far north as Waihi Beach.
Maritime New Zealand's new national on-scene commander Nick Quinn said the shifting of the Rena combined with the weather would result in a "significant" amount of oil washing up from Mount Maunganui to Papamoa from this morning, spreading to Maketu.
Officials underlined the importance of the 1000 community volunteers who had so far offered to help with the clean-up, particularly once the days stretched into weeks.
Ultimately a lot would depend on what eventuated with Rena because of the quantity of oil left on board.
A 10cm gash to the front section of the fuel barge Awanuia, caused when it collided with the Rena during two failed attempts to connect a fuel line on Monday, had been fixed and the ship was ready to resume taking oil off the ship once the weather improved.
Bruce Anderson, Maritime New Zealand's salvage unit manager, said that once the Awanuia reconnected to Rena, and the ship had fired up its engines in order to heat the fuel oil for pumping, it would take 30 to 40 hours to empty.
He detailed how during big seas on Monday night the Rena had moved from its 11 degrees list to starboard to a three to five degree list, becoming more upright on the reef. It led to between 130 tonnes and 350 tonnes of oil being released into the Bay.
However a couple of hours after he announced this, the crew of a harbour tug reported last night it had listed to 15 degrees.
The movement led to the salvage master reducing the manning on board the Rena, followed by a decision later yesterday morning to remove all the crew, using the pilot ladder down to a Royal New Zealand Navy vessel.
The collision resulted in the master of the Awanui developing a new plan to take the vessel into the Rena backwards, or stern on, rather than frontwards or bow on.
Low altitude flights by technical experts over the Rena yesterday were unable to identify any deformation taking place to the structural integrity of the ship and it was in "relatively good shape".
Mr Quinn said 20 teams would be out cleaning the beaches between Papamoa and Mount Maunganui, including 100 people from the defence forces. He stressed that the community could help but as official volunteers so they did not put themselves at risk and make the situation worse on the beaches.
Mr Joyce gave an "absolute commitment" to clean the beaches to what they were before the stranding.
Once the crew and salvors were back on board the vessel, their first job would be to survey below the waterline to see what additional damage had occurred.
Mr Smith defended the use of the dispersant Corexit against overseas reports that it was toxic. The advice he had been given by the Environmental Protection Society was that it was no more toxic than dishwashing liquid and washing powder.
It was less than ideal, but compared with the damage from heavy oil, it was the best alternative they had. Maritime New Zealand has so far sprayed about 600 litres of Corexit on the slick, with helicopters on standby to continue testing.
Dangerous goods containers holding a material that produced an inflammable gas when combined with water were nearly all in a "safe position" above the waterline.
aThe single dangerous goods container that was exposed to the sea was not leaking.