Dutch firefighters Thursday battled for a second day to douse a blaze on a cargo ship off the Netherlands coast suspected to have been started by electric cars.

The Fremantle Highway, a Panamanian-flagged vessel remained tethered to a salvage ship to keep it in position some 14.5 nautical miles north of the Dutch island of Ameland, the Dutch Coast Guard said.

"The fire is still burning on board," it said.

"The temperature on board remains very high and putting out the fire is difficult," Coast Guard spokesman Edwin Granneman said.

"If too much water lands on the ship it can effect its stability," he told the BNR news radio station.

One sailor died after he and 22 others were rescued from the burning ship, carrying nearly 3,000 vehicles, and forcing some crew members to jump overboard.

The blaze erupted shortly before midnight on Tuesday.

Shoei Kisen Kaisha, the ship's owners have said there was a "good chance that the fire started with electric cars," but added that the cause still needs to be investigated.

Officials said the fire could rage "for days", raising the spectre of an ecological disaster on a nearby chain of islands.

"Later this morning, Coast Guard planes will again fly over the Fremantle Highway to observe the situation," the Coast Guard said Thursday.

Meanwhile outgoing Dutch Infrastructure Minister Mark Harbers said should the Fremantle Highway spring a fuel leak, it could drift away from the Waddensee islands into the North Sea.

"This is due to the currently expected wave and wind direction," Harbers said.

The ship however remained close to Ameland, that is part of an archipelago of ecologically sensitive islands situated in the Waddensee.

The area spanning the Netherlands, Germany and Denmark has been declared a UNESCO World Heritage Site and has a rich diversity of more than 10,000 aquatic and terrestrial species.

"The risk of an environmental disaster is always present," Granneman said. "You have to take into account a scenario in which the ship capsizes or sinks."