The Filipino captain of a ship stuck on a New Zealand reef was arrested and charged Wednesday as up to 70 containers fell into rough seas and a black tide of oil washed up on beaches.

Mauro Balomanga appeared in a Tauranga city court amid a heavy police presence charged with operating a vessel in a manner causing unnecessary danger or risk as New Zealand grapples with its worst maritime pollution disaster.

Balomanga was bailed to reappear on October 19 with the court ordering media not to publish pictures showing his face after his lawyer expressed fears that "the public may take matters into their own hands" with anger running high.

According to local reports, Balomanga had captained the ship only since March. The charge carries a maximum penalty of NZ$10,000 ($7,800), or 12 months in jail.

Up to 300 tonnes of heavy fuel has leaked into the environmentally sensitive Bay of Plenty since the Liberian-flagged Rena hit the Astrolabe Reef, 22 kilometres (15 miles) off the North Island coast, last Wednesday.

Overnight, containers began plunging off the stricken vessel in heavy seas, Maritime New Zealand (MNZ) said, but none of them contained hazardous material.

It was highly likely more containers will topple off because of the severe weather conditions and the vessels heavy list, MNZ said, despite tying them down tightly to prevent them falling in.

"There are 1,368 containers on board. Eleven containers containing hazardous substances are still on the vessel and are not among the 70 estimated overboard," an MNZ statement said, adding major shipping had been re-routed.

An aerial survey, likely to go ahead later in the day when the weather improves, would give a clearer indication of exactly how many containers had crashed into the increasingly choppy waters, the maritime body said.

MNZ, which has issued an emergency telephone number for the public to call if they see any of the containers on the beaches, warned people they would be prosecuted if they tried to take what was inside them.

Radio New Zealand reported a floating crane was en route from Singapore to move the rest of the containers off the Rena, which is now listing at a precarious angle.

On Tuesday, the ship issued a mayday and nearby boats, including six navy vessels, scrambled to evacuate a salvage crew when the Rena shifted position on the reef as it was pounded by huge waves.

Officials have warned that New Zealand faces a major disaster if the Rena breaks up on the reef and releases all 1,700 tonnes of oil on board, describing fuel offloading as the "top priority".

Compared to some of the world's worst oil spills, the disaster remains small -- the Exxon Valdez running aground in 1989 in Alaska dumped 37,000 tonnes of oil into Prince William Sound.

But it is significant due to the pristine nature of New Zealand's Bay of Plenty, which teems with wildlife including whales, dolphins, penguins, seals and rare sea birds.

While lumps of toxic sludge began making landfall Tuesday, residents in the suburb of Papamoa awoke Wednesday to a black tide as thick waves, topped with a dark foamy scum, washed dead birds and fish onto the shore.

"I can smell it from my house," local artist Peter Cramond, who lives 400 metres (1,300 feet) from the beach, said as he leaned on his walking stick in howling winds and driving rain.

"I haven't slept all night knowing what's happening here to all the bird and sea life. It's horrible."

Local residents said they had collected large numbers of dead birds and fish on beaches, while a wildlife rescue centre said it expected to reach its capacity of 500 birds in coming days.