An icebreaker has reached ships trapped in thick ice in Russia's Northern Pacific since December 30.

Over 400 seamen have been stranded for close to a week off the coast of Russia's Khabarovsk Territory.

Three ships were trapped 11 miles from the coast of the Khabarovsk Territory - a fishing vessel, a refrigerated freighter, the Bereg Nadezhdy, and the scientific research ship Professor Kizevetter.

Two others, the freezer ship Anton Gurov and trawler Cape Elizabeth, which became icebound on Monday, are about 20 miles away, according to Russian news agency Itar-Tass.

If the situation should suddenly become worse, another icebreaker, the Magadan, currently located not far from the stranded ships in the Gulf of Sakhalin, will be sent to aid the operation.

The icebreaker Krasin has also been dispatched from the De-Kastri port in the Tatar Strait and is moving in the direction of the stranded ships.

The weather on the Okhotsk Sea is currently favourable, but could change at any moment, and officials are not willing to make a prediction on how long the rescue effort may take.

The State Marine Rescue Centre said the crews had sufficient food and water supplies and are not in danger.

In winter, the Sakhalin Bay is considered one of the most dangerous maritime regions of the Okhotsk Sea with few clear water gaps on its surface. Mariners risk the conditions to net huge profits on the sea's store of herring and pollock.