Royal Dutch Shell on Monday said it was delaying until next year exploratory drilling for oil in offshore Alaska after suffering damage to a dome used to contain any potential spills.

"The time required to repair the dome, along with steps we have taken to protect local whaling operations and to ensure the safety of operations from ice floe movement, have led us to revise our plans for the 2012-2013 exploration programme," the Anglo-Dutch group said in a statement.

"In order to lay a strong foundation for operations in 2013, we will forgo drilling into hydrocarbon zones this year," it added.

Shell's search for oil in the region is facing deep opposition from environmentalists, who worry that an oil spill could have devastating effects on the pristine Arctic environment.

Shell said in its statement on Monday that "during a final test, the containment dome aboard the Arctic Challenger barge was damaged."

It added: "It is clear that some days will be required to repair and fully assess dome readiness.

"We are disappointed that the dome has not yet met our stringent acceptance standards; but, as we have said all along, we will not conduct any operation until we are satisfied that we are fully prepared to do it safely."