A cargo ship headed for Germany's Bremerhaven which was caught in rough North Sea weather lost at least 270 containers, including four holding potentially dangerous substances, the Dutch and German coastguards said Wednesday.

The Panama-registered MSC Zoe shed the containers containing mostly toys, furniture and auto spare parts while battling a storm, that was dubbed 'Zeetje' off the Frisian Islands, an archipelago off the northwestern Dutch coast also known as the Wadden Islands.

So far, around 20 containers have been located near the shores of these islands while another six were found in German waters.

Later on Thursday it emerged that a bag containing dangerous powder washed up on a small Dutch island.

“A bag containing 25 kilogrammes (55 pounds) of powder was found on the beach of Schiermonnikoog,” said Jan-Willem Zwart, spokesman for the security services of the Frisian Islands, identifying it as “organic peroxide,” a
highly flammable substance used in making plastics.

He told AFP the bag had come from one of three containers transporting organic peroxide that had been on board the MSC Zoe.

The storm also caused flooding and other damage in northern Germany.

The Dutch coastguard had earlier tweeted that three of the containers contained, in powder form,  highly flammable, potentially dangerous organic peroxides used in making plastics which can cause irritation if breathed in.

On Wednesday the Dutch coastguard tweeted the location of where the containers went overboard. They provided updates all day.

German coastguard sources said they had located one container holding organic peroxide among six containers that reached the country's coastline.

They also warned the public not to touch the containers if found, but to call police or the fire brigade.

The Dutch coastguard said the containers went overboard not far from the German island of Borkum. The cargo ship was mostly carrying toys, furniture and auto parts.

Dutch broadcaster NOS showed local people around one of the containers and pictured toys and other materials strewn across beaches as well as one man carrying off a flat screen television.

A Dutch coastguard spokesman told NOS it was likely the containers holding the peroxides had sunk.

A Dutch coastguard plane was due to undertake a new search on Thursday morning while strong winds were hampering the MSC Zoe's own attempts to carry out an inventory.

The mayor of Terschelling island, where some of the cargo washed ashore, told NOS he expected it would take several days to clear the beach of stray items from the containers.

The 2015-built MSC Zoe, which was headed to the northern German port of Bremerhaven, is one of the world's largest container vessels at 396 metres long and 59 metres wide.

Storm 'Zeetje'

It came as German cities reported flooding after the storm hit the mainland. Zeetje kept emergency forces in northern Germany on their toes on New Year's Eve as it triggered the first storm surge of the new year on the Baltic Sea coast.

In Wismar, Mecklenburg-West Pomerania, streets were flooded on Wednesday after the water level rose.

Ferry connections around the seaside resort of Warnemünde, including the connection between Rügen and Hiddensee, were temporarily suspended.

The first storm of the year also caused some delays and train cancellations in the area.

High water levels in Wismar on Wednesday. Photo: DPA

Also on the Baltic Sea coast in Schleswig-Holstein, water levels rose above normal. In Lübeck and Flensburg, cars were under water. The police reported that in both cities, as well as in Kiel, waterlogged riverside roads had to be temporarily closed. No major damage had been reported in the afternoon on Wednesday.

In Hamburg, emergency services had to lift two large fallen trees from the street with a crane, a fire brigade spokesman said on Wednesday. Among other things, the trees had damaged several cars.