"No people were injured and no damage caused to the installation beyond the equipment directly involved. But the (Norwegian Petroleum Safety Authority) PSA considers the incident to have had a substantial potential," the PSA said in a statement.

The leak occurred on September 12 on the Ula field, in the Norwegian waters of the North Sea.

Production at the site, which reached some 10,000 barrels of oil per day in July according to the Petroleum Directorate, has been suspended since the incident, PSA said.

A spokesman for BP in Norway told Dow Jones Newswires the company had launched its own investigation but that it was too early to determine how much oil and gas had leaked out.

Copyright AFP (Agence France-Presse), 2012