Rescuers looking for survivors of a Russian oil rig that capsized and sank on Sunday amid a storm are losing hope that they could still find anyone else alive after over 24 hours in the icy waters of the Okhotsk Sea in Russia's far eastern coast, 200km off Russia's Sakhalin island.

The Kolskaya rig sent a distress signal at 11.25am Sunday (NZ time). Sixty seven people were on board the oil rig.

The crew was about to be evacuated by helicopter but the platform capsized and sank before they could board their rescue rafts, regional ministry spokesman Taimuraz Kasayev told the AFP, adding the portholes were damaged by ice and waves, making way for water to go into the vessel.

Fourteen people were saved by vessels accompanying the rig, while 16 bodies had been found.

Waves reaching six metres and strong winds hampered immediate rescue efforts amid a storm and temperatures of minus 7 degrees Celsius.

Kolskaya was working for a unit of state-controlled gas export monopoly Gazprom.

The Emergencies Ministry, which usually coordinates rescue operations, declined to confirm a raft had been spotted and it was unclear whether anyone could still be alive after more than 24 hours adrift in the depths of winter.

Thirty seven people are still unaccounted for in the icy waters of Sea of Okhotsk, which is a vast expanse of water more than twice the size of France, according to Reuters.

"Until all the people are found the rescue operation will not be concluded," Natalya Salkina, a spokeswoman for federal transport investigators in Russia's far eastern city of Khabarovsk, told Reuters by telephone.

"You can always hope for a miracle," she added.