It is the first time the African nation has imposed a fine on a company operating in its waters.

The ministry for the environment and fisheries said in a statement that a spill earlier in June from ChevronTexaco's offshore platforms in northwest Angola polluted beaches and forced fishermen to stop work.

A government investigation found that the spills were the result of leaks from poorly maintained pipes used to transport crude from the platforms, the statement said.

The fine was handed down as Chevron met President Fradique de Menezes of Sao Tomea, a small island nation off Angola's coast, to discuss oil exploration.

Old pipes

Angola is sub-Saharan Africa's largest oil producer after Nigeria, exporting 800,000 barrels of oil per day and delivering more crude oil to the US than Kuwait.

Investigations in May and June showed that the spills at the Cabinda oil field were caused by obsolete tubing.

Chevron has promised to invest $108m replacing the pipes.

The company, which pumps almost three-quarters of Angola's oil, last week reduced crude production by about 55,000 barrels per day, or 12%, after a leak at a crude pipeline.

Chevron's operations have been repeatedly blamed for oil spills by the local press and environmental activists.