Oil giant Shell put its controversial oil drilling plans for the Alaskan Arctic on hold through 2013, following multiple embarrassing problems with its two drilling rigs.

The company said it would freeze exploration drilling in the Beaufort and Chukchi Seas on Alaska's northern coast until 2014 "to prepare equipment and plans for a resumption of activity at a later stage."

"We've made progress in Alaska, but this is a long-term program that we are pursuing in a safe and measured way," said Shell president Marvin Odum in a statement.

"Our decision to pause in 2013 will give us time to ensure the readiness of all our equipment and people following the drilling season in 2012."

Shell's use of old drilling rigs, the Noble Discoverer and the Kulluk, came under fire following several incidents.

The Kulluk washed ashore after breaking loose from towing vessels in stormy seas in southern Alaska in January.

The Noble Discoverer was recently cited by the US Coast Guard for numerous safety and operational deficiencies.

Shell has sent both to Asia for maintenance and repairs.

Shell said it had completed top-hole drilling for two wells in the Arctic in 2012, the first drilling in the region in more than a decade.

"This drilling was completed safely, with no serious injuries or environmental impact," it said Wednesday.

But activists opposed to drilling in the Arctic say Shell's precautions are inadequate.

Environmental advocate group Greenpeace has strongly attacked Shell's use of decades-old drilling rigs in the challenging Arctic waters.

"Both the Noble Discoverer and the Kulluk are aging, rusty vessels and not the state of the art fleet that Shell has been boasting about," the organization said last month.

US Congressman Ed Markey called Shell's move Wednesday "the right decision."

"After bumbling through a year of mishaps, beachings, and complete safety failures, it's clear that Shell and the oil industry were not ready to drill in the Arctic," Markey said in a statement.

"This postponement is the right decision and should allow the Department of Interior the time it needs to do a full review of the oil industry's capability to handle the harsh conditions in the Arctic."