Russian authorities have issued visas to seven members of a Greenpeace ship's crew that will allow them to leave the country after dropping criminal charges against them over a protest outside an Arctic oil rig.

Greenpeace said on Thursday that other foreign members of the crew were expected to get their exit visas soon.

The 30 people were arrested in September after a protest outside a Russian oil rig and spent two months in jail before they were granted bail in November.

Hooliganism charges were dropped after Russia's parliament passed an amnesty law that was seen as an attempt by the Kremlin to assuage the criticism of the country's human rights record before the Winter Olympics in Sochi in February.

Greenpeace said Anthony Perrett of Britain was the first to get the visa in his passport on Thursday.

"This was the final step," Perrett said in a statement released by the group. "I'll be leaving for home in Wales as soon as possible now, extremely proud of what I did three months ago. We took peaceful action to defend a part of the world that is the heartbeat of our climate."