Sea Shepherd conservation group leader Paul Watson has been arrested in Germany and faces deportation to Costa Rica on possible charges stemming from a high seas confrontation over shark finning.

Mr Watson, who has been on a speaking tour and searching for a new anti-whaling vessel, was detained in Frankfurt while travelling to France on an alleged violation of ship's traffic law, Sea Shepherd said.

Paul Watson faces deportation to Costa Rica after being arrested.

But a media report from Costa Rica claimed he faced an outstanding warrant for attempted murder in the 2002 incident.

"The specific 'violation of ship's traffic' incident took place on the high seas in Guatemalan waters, when Sea Shepherd encountered an illegal shark finning operation, run by a Costa Rican ship called the Varadero," the conservation group said in a statement.