The operator of a Japanese bulk carrier which ran aground off Mauritius in the Indian Ocean apologized on Sunday for a major oil spill which officials and environmentalists say is creating an ecological disaster.

A man scoops leaked oil from the vessel MV Wakashio on Saturday. Photo: AFP

The MV Wakashio, operated by Mitsui OSK Lines, struck the reef on Mauritius' southeast coast on July 25.

"We apologize profusely and deeply for the great trouble we have caused," Akihiko Ono, executive vice president of Mitsui OSK Lines, said at a new conference in Tokyo.

He added that the company would "do everything in their power to resolve the issue."

At least 1,000 tons of oil is estimated to have leaked from the ship onto the waters surrounding Mauritius. Some 500 tons of oil have been salvaged from the ship, but there are still 2,500 tons remaining on the ship.

Neither Mitsui OSK Lines nor Nagashiki Shipping, the ship's owner, could confirm the cost of damages from the oil spill.

"Thousands of species around the pristine lagoons of Blue Bay, Pointe d'Esny and Mahebourg are at risk of drowning in a sea of pollution, with dire consequences for Mauritius' economy, food security and health," Greenpeace said in a statement.

Satellite images released on Friday showed a slick spreading out into the turquoise waters surrounding the stricken vessel. Some fuel has washed ashore.

France was sending specialist teams and equipment to help Mauritius deal with the spill, French President Emmanuel Macron said. 

A French military aircraft from the neighboring island of Reunion was sent to the spill site on Saturday. "When biodiversity is in danger, there is an urgent need to act," Macron said. "You can count on our support."

 Mauritius declared a state of "environmental emergency" on Friday following the accident.