Danish Maersk Oil on Wednesday shut down a North Sea rig after oil was observed on the surrounding water.
Production will resume when the technicians have located the source of the leak and made the necessary repairs, the company said, adding that a later surveillance sweep by a helicopter showed that "the leakage has stopped".
Early in the day another helicopter crew first noticed the leak.
"A helicopter flying between the Maersk Oil operated Gorm and Rolf platforms observed oil on the water," the company, a subsidiary of Danish A.P. Moeller-Maersk, said in a statement.
"Oil production from the Rolf platform was stopped immediately. This afternoon a helicopter surveyed the area and reports that the leakage has stopped," it added.
Maersk said it was monitoring the situation and had activated its oil spill contingency plan, including two 1,200 metre floating boom barriers which are being transported from Denmark.
The first of those vessels was expected to be in position in the early hours of Thursday.
Maersk Oil said it was also mobilising "a remote operating vehicle (ROV) that can investigate if there is a breach in the (17 kilometre) pipeline between the Rolf and Gorm platforms."
Danish authorities have been informed.
"We take the slightest leak very seriously," Maersk Oil spokesman Thomas Groendorf told AFP.
The Rolf platform is produces 400 barrels of oil per day and is some 220 kilometres west of the Danish port of Esbjerg.
Maersk Oil produces around 200.000 barrels per day from its North Sea oil platforms.
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