British energy company BP and the National Iranian Oil Co. control the Rhum natural gas field in the North Sea. The British economy became a net importer of natural gas in 2009 and sanctions targeting Iran's energy sector idled the Rhum field a year later.
A spokesman for the British Department of Energy and Climate Change was quoted by British newspaper The Mail on Sunday as saying it was reviewing the North Sea project.
"We are working to ensure the long-term security of the Rhum gas field, but no decision has been made at this time," the spokesman said.
The newspaper reported Sunday that European Union officials said operations at Rhum could be waived from sanctions under certain circumstances but the report did not elaborate. BP did not provide a comment.
Iran holds a minority stake in the Shah Deniz gas field in the Azeri waters of the Caspian Sea. A BP-led consortium is gearing up to export some of that natural gas to the European market.
Sanctions on Iran's energy sector are designed to starve the government of revenue it could use to finance a controversial nuclear program.