DONG Energy A/S said it has shut the Danish Siri field and two associated fields after discovering cracks in part of the platform.

The company said the cracks were found during routine maintenance in a small tank attached to Siri platform's 50,000 cubic-meter subsea oil storage tank. It has halted output while the causes are studied.

DONG spokesman Ulrik Frohlke said: "So far we are just looking into the nature of the problem. We have one yearly routine inspection of subsea installations. Last year's showed nothing, but now we see these cracks."

He couldn't give an estimate for how long Siri will be offline. The field, located on the Danish continental shelf close to the Norwegian border, produced 1.91 million barrels of oil equivalents in 2008.

Two other fields, Nini and Cecilie, are tied back to Siri.

DONG is the operator of the field, with a 50% stake, and Norway's Noreco (NORECO.OS) also owns a 20% stake. Noreco said in a statement: "Further investigation and analysis over the next couple of days will provide more information and timing for restart of the Siri production."

Independent Canadian upstream oil and gas company Talisman (TLM) holds the remaining 30% stake in the field.

Company Web site: www.dongenergy.com

-By Elizabeth Adams, Dow Jones Newswires; +44 (0) 20 7842 9386; elizabeth.adams@dowjones.com