The US government says it will offer exploration rights for oil and gas in a north-western region of Alaska.
The area holds huge reserves in oil and gas
The federal Minerals Management Service said it would take bids next month for concessions in the Chukchi Sea, which separates Alaska from Siberia.
But environmental groups fear the effects on wildlife in the region, including the polar bear population.
There have been no lease sales for over 15 years and the groups fear further exploration could damage marine life.
Energy exploration in Alaska has always been a tough choice between preserving one of the planet's last great areas of pristine wilderness and the potential for huge profits to be made from its development.
The American sectors of the Chukchi Sea are believed to hold 15bn barrels of recoverable oil and over two trillion cubic metres of natural gas.
But the authorities had not held a lease sale in the sea since 1991, both due to the difficulties and cost involved in extraction from the Arctic continental shelf and concerns over the environment.
There are fears for the polar bear population
The Minerals Management Service says exploration will not be allowed to take place any closer than 80km (50 miles) from the shoreline, therefore striking a balance between development and protection of coastal resources.
But ecologists say any further exploration could have a major impact on marine life, with polar bears one of the hardest-hit species.
The Chukchi Sea is home to one of two populations of polar bears in the US, and their numbers have already been depleted by loss of habitat due to global warming.
Many protestors are angry at the timing of the announcement, which comes days before the US Fish and Wildlife Service decides whether to list the polar bear as a threatened species.