Hopes of refloating a ship that went aground off the South African coast are fading, say experts attempting to salvage the vessel.

The ship - the Jolly Rubino - caught fire last week and went ashore off the Saint Lucia Wetland, an environmentally sensitive site.

The vessel is being pounded by surf and the cracks in its hull are getting larger, conservationists say.

Wildlife home

Saint Lucia is a sanctuary for: Hippos Crocodiles Pelicans Flamingoes Estuarine fish Mangrove forests

Officials are deciding whether to try to salvage the ship, or pump the remaining 750 tonnes of fuel from her hold.

Booms have been put in place in an attempt to prevent the oil slick from coming ashore.

Smit Salvage had made an unsuccessful bid to put out the fire, which broke out last Tuesday, crippling the vessel and forcing the crew to abandon ship.

But on Monday the fire continued to burn on the freighter, which contains toxic chemicals.

Environmentalists have expressed concern about the impact on wildlife in the area.

The Jolly Rubino ran aground about 11 kilometres south of the Unesco-recognised wetlands.

The sand around the ship was streaked with heavy fuel oil, and larger patches of oil have been spotted floating near the shore.

Ship cracked

About 400 tonnes of oil are believed to have escaped through a 20 metre crack in the ship's port side.

Crisis management officials held a brief debate over whether to declare the wreck a national disaster, but decided instead to label it a "major incident" after concluding that the situation was not yet out of hand.

The 22 crew of the Jolly Rubino were airlifted to safety last Tuesday and the ship's dog was rescued on Friday.

The ship had left Durban in South Africa for a journey to Mombasa, Kenya.