An estimated four to five barrels of oil were lost in the spill

The eastern half of the site has been shut after corrosion was found in pipes following a small spillage.

BP has been told by the US government that there is no need to close the western portion of the giant plant.

The governor of Alaska has questioned whether the firm misled it over maintenance checks on its pipes.

Daily checks

A BP spokesman said it was "pleased" that the Department of Transport was "not aware of any data concerning the current condition of the pipe in the western operating area that it believes would necessitate an immediate shutdown of operations on the line".

The company agreed to a government demand that it carry out rigorous daily checks on the pipelines it kept open.

BP has said it will replace 16 miles of pipeline at the site after corrosion was discovered on an oil transit line.

The UK oil giant owns a quarter of Prudhoe's output, the remainder being owned by ConocoPhillips and ExxonMobil.

Estimates suggest repairs will cost BP about $100m (�52.7m).

The shutdown at the site is expected to cost Alaska $6.4m a day in tax revenues and this has prompted a government state-wide hiring freeze.

Supply pressure

Prudhoe Bay produces about 400,000 barrels per day (bpd) and the loss of this supply comes at a time when the conflict in the Middle East and concerns about supplies from Nigeria have prices to record highs.

The International Energy Agency said on Friday that while the world could cope with current shortfalls, the pressure was on oil producers' group Opec to fill the gap.

It estimated the cartel would have to release 600,000 bpd in the third quarter of 2006 and an extra 200,000 bpd in the last three months of the year.

Oil prices had slipped 3% on Thursday as traders feared demand for air travel could fall after UK police said they had disrupted a plot to blow up UK flights to the US.

However, prices rebounded on Friday, with Brent crude up 55 cents to $75.83 - about $3 below the record high induced by the Prudhoe Bay leak. US light, sweet crude rose 45 cents to $74.45.