Norwegian energy group StatoilHydro reported a serious oil leak at its Statfjord oilfield in the North Sea on Saturday and said it evacuated all but emergency workers from platform A.

Oil production on the platform had been stopped, it said. "The situation is serious and confused," StatoilHydro said in a statement.

No one is hurt or missing and clean-up crews have been mobilised to deal with the spill, the company said.

Oil was leaking from one or more storage cells, and for the sake of safety oily water was being discharged to sea, Norway's biggest oil and gas producer said.  "There is an internal leak in the platform, and we have been pumping some polluted water from the foundation into the sea," StatoilHydro spokesman Gisle Johanson said.

"So the amount of oil pumped to sea is limited."  Three vessels with oil containment booms are in operation at the field, Johanson said and added: "But it is fairly limited amounts (of oil) at sea."

Production at platform A was halted early on Saturday, Johanson added. An estimate of the production impact was not immediately available.

"During work on a pipe on the platform an oil leak occurred in one of the three shafts," the company said.  Two workers who were exposed to gas have received medical care and are feeling well after being removed to the B platform, the company said.

There were 217 people on board when the leak occurred, the company said. "All personnel, apart from the emergency response team, have been evacuated."

The ageing Statfjord oilfield, which straddles the Norwegian-UK boundary line, was once the biggest oilfield in the North Sea. Production from three platforms has fallen from a 1987 peak of 850,000 barrels to roughly 150,000-160,000 barrels of oil per day.

Oil is also produced from satellite fields tied to Statfjord, bringing total output from the platforms to about 470,000-480,000 barrels per day.-Reuters