The Sea Shepherd Society's anti-whaling and the Japanese whaling ship Yushin Maru No.3 collide in the waters of Antarctica on Saturday. (Institute of Cetacean Research/Associated Press)

The Bob Barker anti-whaling ship and a Japanese harpoon boat collided in icy Antarctic waters Saturday in the second major clash this year in increasingly aggressive confrontations between conservationists and the whaling fleet.

No one was injured in the collision, which each side blamed on the other.

The U.S.-based activist group Sea Shepherd, which sends vessels to confront the Japanese fleet each year, accused the Japanese ship of deliberately ramming the Bob Barker — named after the former game-show host who donated millions of dollars for the anti-whaling group to buy it.

But Japan's Fisheries Agency said the activist boat caused the collision by suddenly approaching the harpoon vessel No. 3 Yushin Maru to throw bottles containing bad-smelling butyric acid at the Japanese ship.

The agency accused Sea Shepherd of "an act of sabotage" and noting the Japanese expedition is allowed under world whaling regulations as a scientific expedition. Conservationists call the annual hunt a cover for commercial whaling.

Neither side's account could be verified. Video shot from the Bob Barker and released by Sea Shepherd shows the two ships side by side, moving quickly through the water. The ships come closer together and the Japanese ship then appears to turn away, but its stern swings sharply toward the Bob Barker.

The collision is obscured by spray, but a loud clanging noise can be heard before the vessels separate.

Sea Shepherd founder Paul Watson said a one-metre-long, 10-centimetre-wide hole was torn in the Bob Barker's hull, but it was above the water line and was not a threat to the ship. The Japanese agency said Yushin Maru sustained minor damage to its handrail and hull.

The collision was the second this year between a Sea Shepherd boat and the Japanese fleet.

On Jan. 6, a Japanese whaler struck Sea Shepherd's high-tech speedboat Ady Gil and sheared off its nose. The Bob Barker then came to rescue the crew of the Ady Gil, which sank a day later.

The governments of Australia and New Zealand, which have responsibility for maritime rescue in the area where the hunt is usually conducted, say the fight between the two sides is becoming increasingly dangerous and have repeatedly urged them to tone it down.