TOKYO, Aug 4 (Reuters) - Japanese ship leasing company Shoei Kisen Kaisha, owner of the car carrier Fremantle Highway that caught fire off the Dutch coast last week, said on Friday it will investigate the cause of the incident in cooperation with relevant parties.

The blaze broke out on July 26 as the Panama-registered ship was travelling from Germany to Egypt with nearly 3,000 vehicles on board, killing one crew member and injuring seven others who jumped overboard to escape the flames.

Local officials said the carrier arrived at the northern Dutch port of Eemshaven for salvage on Thursday.

An investigation has been launched by the Panama Maritime Authority, and the Netherlands was expected to assist the inquiry, a Dutch Safety Board spokesman said.

Shoei said in a statement that all 22 people who were hospitalised due to the incident, including the captain, had been discharged from the hospital by Thursday.

Kawasaki Kisen Kaisha, or "K" Line, the Japanese shipping company that had chartered the Fremantle Highway, also said on Friday that the vessel's owner would investigate the extent of damage and cause of the accident in cooperation with the authorities.

"K" Line previously said there were 3,783 vehicles on board the ship, including 498 battery electric vehicles.

An emergency responder was heard in a recording released by Dutch broadcaster RTL as saying "the fire started in the battery of an electric car." Authorities have not confirmed whether that is the case, however. (Reporting by Kantaro Komiya; editing by John Stonestreet and Hugh Lawson)