Brisbane - Ten times more oil than originally thought leaked from a ship to blacken miles of white sand beaches along Australia's northeast coast, a government official said Saturday.

Authorities declared a disaster zone along 37 miles (60 kilometers) of some of Australia's most popular beaches in Queensland state after they were covered in a blanket of heavy fuel oil that spilled from a ship hit by rough seas on Wednesday.

Queensland state Deputy Premier Paul Lucas told Australian Broadcasting Corp. radio Saturday that officials originally thought between 5,300 and 7,900 gallons (20,000 and 30,000 liters) of oil had leaked from the ship. Lucas said it is "now apparent" that the amount of oil spilled was around 60,700 gallons (230,000 liters). He did not explain how he arrived at that estimate or offer any further details.

Anthony Tregoning, spokesman for Britain's Swire Shipping Ltd., the Hong Kong-registered ship's owner, said the company would not be releasing any further figures on how much oil had spilled.

Queensland officials accused the company of initially misleading the government about the size of the spill. Premier Anna Bligh said the company told the government the spill was much smaller, leading officials to predict there would be little environmental damage.

Swire said containers of fertilizer had slipped from the ship's deck as it rocked in rough seas, ripping a hole in a fuel tank and spilling more than 11,000 gallons (42,500 liters) of oil into the sea. On Friday, the company said an inspection of the hull led it to conclude the amount of spilled oil was "significantly more" than that, but did not give a figure.

National parks at Moreton and Bribie islands just north of the state capital of Brisbane were hardest hit by the oil, and fuel also washed ashore in pockets along the Sunshine Coast.

Hundreds of government workers trudged along beaches Saturday, scooping up black, sludgy sand and throwing it into bags. Bligh said most of the cleanup on the Sunshine Coast and Bribie Island was completed Saturday, though the cleanup of Moreton Island was expected take longer.

The Environmental Protection Agency said no dead wildlife had been discovered so far.

The Australian Maritime Safety Authority said the ship, brought to port still leaking oil, would not be allowed to leave until officials were satisfied the spill had been explained. Queensland officials threatened the shipping company with a multimillion-dollar lawsuit.

Under Australian law, the ship's owners face fines of up to 2 million Australian dollars ($1.3 million) and could be liable for up to AU$250 million ($160 million) more in penalties for causing environmental damage.

In a statement, Swire said it regretted the extent of the pollution caused by the spill and said the company and its insurers were talking with the government about cleanup costs.