Updated

Sea Shepherd is asking Dutch authorities to prosecute Japanese whalers for allegedly attacking the radical conservationist group's ships in the Southern Ocean.

Lawyer Liesbeth Zegveld has filed a criminal complaint with Dutch prosecutors accusing the crew of the Nisshin Maru whaling ship of deliberately ramming Sea Shepherd's ships in January.

The case is being brought in the Netherlands because the Sea Shepherd ships Steve Irwin and Bob Barker both sail under the Dutch flag.

It intensifies a legal battle going on between Sea Shepherd and Japan's whaling fleet stemming from their repeated clashes on the high seas in recent years.

In the complaint announced Thursday, Zegveld accused the Nisshin Maru and shipping company Tomoyuki Ogawa of crimes including "sea robbery" a little-used offense formerly used to prosecute pirates.