June 3 (Bloomberg) -- Royal Dutch Shell Plc and StatoilHydro ASA may be forced to cut as much as 220,000 barrels a day of North Sea oil production, about 9 percent of Norway's total output, if rig managers strike this weekend.

StatoilHydro ASA, Norway's largest oil company, said a potential strike would shut down about 150,000 barrels a day of production from its Snorre A and Vigdis platforms. The strike may also crimp production at Shell's Draugen A platform, spokeswoman Kitty Eide said in a phone interview today. The Draugen field pumps about 70,000 barrels a day of oil.

Norwegian oil rig managers are threatening to stop work at Snorre and Draugen on June 7, should talks over wages and benefits with employers before a government mediator fail. Sixty of the workers that would go on strike as of that date work at Statoil's Snorre A, company spokesman Torstein Stangenes said.

``Should the strike take place, we would have a total production stop after a couple of days,'' he said today on the phone from Bergen. ``A production stop at Snorre A would also mean a limited production cut at Snorre B.''

Twenty-six workers from Draugen may be involved in the strike if it goes ahead, Eide said. They work different shifts.

Norway's oil production, including natural gas liquids and condensate, is estimated at 2.4 million barrels a day in 2008, according to the Petroleum and Energy Ministry. The country is the world's fifth-biggest supplier of crude.

To contact the reporters on this story: Alexander Kwiatkowski in London at akwiatkowsk2@bloomberg.netMarianne Stigset in Oslo at mstigset@bloomberg.net;

Last Updated: June 3, 2008 08:23 EDT