Sky News cited the Dutch broadcaster NOS on Wednesday as saying that the ship, the Fremantle Highway, was traveling from Bremerhaven in Germany to Port Said in Egypt with around 3,000 cars on board.
The fire probably started in one of the 25 electric cars on board, the news service added, citing a spokesman for the coast guard.
There are reported to have been 23 people on board the ship when the fire broke out, with a number of those jumping off the vessel before being taken out of the water to safety.
AMK/PR