Emergency workers are battling to contain an oil spill near a joint Kuwaiti-Saudi oilfield in the Gulf, an official said Sunday.

"Emergency oil teams are still struggling to put an oil spill near Kuwait's southern Ras Al-Zour area under control," said Kuwait Petroleum Corporation spokesman Talal al-Khaled in a statement carried by the official KUNA news agency.

There were no official reports on the source or size of the spill in the waters off Kuwait's southern coast, near the joint Kuwaiti-Saudi offshore Al-Khafji oilfield. 

Kuwaiti media however on Sunday quoted local oil experts as saying the spill originated from an old 50-kilometre (31-mile) pipeline from Al-Khafji.

The experts estimated that as many as 35,000 barrels of crude oil may have leaked into the waters off Al-Zour, where Kuwait is building a massive $30 billion oil complex that includes a 615,000-barrel-per-day refinery.

Emergency teams have sealed off two power and water desalination plants in the area to prevent the contamination of drinking water. 

Kuwait depends largely on desalination for its fresh water supplies.

Saudi Arabia and Bahrain, located south of Kuwait along the Gulf coast, said the spill had not reached their waters.

Saudi Arabia said that it had put into action a "crisis management plan" and was conducting an aerial survey of its oil plants along the coast in a statement published by the official SPA news agency.

The Kuwait Petroleum Corporation said teams from Saudi Arabian Chevron and the Oil Spill Response Limited (OSRL) had joined the teams cleaning the coastal waters.

Kuwait is a major producer of oil and gas, which make up around 95 percent of its export revenues.