The 236-meter cargo ship Rena struck the Astrolabe Reef, about 12 nautical miles off the coast near Tauranga Harbour, at around 2. 20 a.m. Wednesday and was listing, said a statement from Maritime New Zealand (MNZ). [Xinhua]

"Salvage experts and naval architects on board are very closely monitoring the ship and have got sensors in place that will provide advance warning if the vessel's structure is coming under too much stress."

Nine oiled birds seven little blue penguins and two shags had been found and were being treated, and 14 teams were checking beaches for more affected wildlife, including seals.

Meanwhile, New Zealand's Maritime Union asked MNZ to publish any reports on the Rena after it received information of "multiple problems," including the ship's charts.

It said an MNZ inspection of the vessel in the port of Bluff found multiple deficiencies on Sept. 28, said the union.

Problems with the charts could a possible clue as to how the vessel ran into the Astrolabe Reef.

Union general secretary Joe Fleetwood said the grounding had developed into a major event with "an increasing danger of very serious outcomes, with threats from oil and chemical spillage, the safe evacuation of crew and the possibility the vessel will break up, creating a major shipping hazard."

"Our view is that the unregulated nature of flag of convenience global shipping will be shown to be the underlying cause of what has happened. We have vessels on the New Zealand coast that are not up to scratch," said Fleetwood

New Zealand ports and waters had seen several "serious incidents" on overseas fishing and cargo vessels, including flag- of-convenience vessels registered in countries with "lax or non- existent regulation," in recent years.

"We have had ongoing incidents ranging from underpayment of wages, failure for crews to be returned home at the end of their contracts, mistreatment and abuse, all the way up to serious injuries and deaths, and the sinking of vessels."

Greece-based Costamare Inc., the parent company of Daina Shipping Co., registered owner of the 3,032-TEU Rena, issued a statement Saturday, saying it was cooperating fully with the New Zealand authorities and every effort was being made to control and minimize the environmental consequences of the grounding.

It said the Rena, which was built in 1990 and had a deadweight tonnage of 47,230, was carrying 1,351 containers when it grounded.

The 236-meter Rena was reportedly carrying milk powder, timber, meat, fish and a small amount of the hazardous material ferrosilicon, an alloy of iron and silicon used in making cast iron and steel, when it ran aground.