The Irene SL, a Greek-flagged oil-laden supertanker pirated off Oman was headed toward the Somali coast on Thursday, but there has been no contact with the ship, the Combined Maritime Forces said.

"The only thing that has changed is its position, and at 0400 Zulu (GMT) ... it was 150 nautical miles (277 kilometres) southeast of the Omani coast, heading toward the Somali coast," a spokeswoman for the Bahrain-based international naval force told AFP by telephone.

There has been "no communication with the ship to date," since its hijacking about 220 nautical miles (370 kilometres) east of the Omani coast on Wednesday, she added.

Asked about the potential for a rescue operation, she said that "we consider all options, but at the moment, the situation is just being kept under review."

An official from Enesel, the Greek company that manages the ship, said on Wednesday that the tanker was carrying "about 270,000 metric tons" of Kuwaiti crude, which he said translates to over 1.9 million barrels of oil.

The European Union's Atalanta mission to the seas off Somalia and the Gulf of Aden (EUNAVFOR) said the 319,247-tonne ship is both Greek flagged and owned, and said it was travelling from Fujairah in the United Arab Emirates to Suez when it was hijacked.

"She has a crew of 25 (seven Greek, one Georgian and 17 Filipinos). There is presently no communication with the vessel and no information regarding the condition of the crew," EUNAVFOR said.

Enesel's website says the tanker is 333 metres (1,092 feet) long with a 60-metre (196-foot) beam.