Lawyer Liesbeth Zegveld filed a criminal complaint with Dutch environmental prosecutors accusing the crew of the Nisshin Maru whaling ship of deliberately ramming Sea Shepherd's ships in February.
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.
Japan says it hunts whales for scientific purposes, an allowed exception to an international whaling ban, though anti-whaling activists say the hunts are a cover for commercial whaling.
Zegveld accused the Nisshin Maru's captain Tomoyuki Ogawa and his crew of crimes including "sea robbery" a little-used offense formerly used to prosecute pirates. The charge has recently been dusted off in the Netherlands to prosecute Somali pirates captured by the Dutch navy.
"The Nisshin Maru is guilty of piracy, violence against the crew of a sea vessel endangering safe navigation and the destruction of Sea Shepherd vessels; all three punishable offences under the Dutch Criminal Code," Zegveld said in a statement.
After one of the incidents Zegveld
Zegveld's complaint accused the whalers of deliberately ramming the Sea Shepherd vessels during refueling operations in the Southern Ocean on Feb. 20 and 25.
It is the second time Zegveld has attempted to have Japanese whalers prosecuted on behalf of Sea Shepherd. Prosecutors declined to open a prosecution in 2010, but Zegveld says circumstances have now changed, because both the Steve Irwin and Bob Barker ships sail under Dutch flag, giving prosecutors a stronger foundation for laying charges.
"The Public Prosecutor's Office must now accept its responsibility and cannot argue that there is insufficient Dutch interest to bring a prosecution or refuse to do so for other reasons," Zegveld said.
The Dutch complaint follows a significant courtroom defeat for Sea Shepherd.
Last month, the 9th U.S. Circuit Court of Appeals castigated Sea Shepherd and its founder Paul Watson for their tactics in disrupting the annual Japanese whale hunt in the treacherous waters of Antarctica.
"You don't need a peg leg or an eye patch," Chief Judge Alex Kozinski wrote for the unanimous three-judge panel. "When you ram ships; hurl glass containers of acid; drag metal-reinforced ropes in the water to damage propellers and rudders; launch smoke bombs and flares with hooks; and point high-powered lasers at other ships, you are, without a doubt, a pirate, no matter how high-minded you believe your purpose to be."
The ruling overturned a Seattle trial judge's decision siding with the protesters and tossing out a lawsuit filed by a group of Japanese whalers seeking a court-ordered halt to the aggressive tactics, many of which were broadcast on the Animal Planet reality television show "Whale Wars."
Meanwhile, Australia is challenging the legality of Japan's whaling at the United Nations highest judicial organ, the International Court of Justice in The Hague.