Anti-whaling activists have released evidence that Japanese ships inside a Southern Ocean sanctuary were killing whales.

Sea Shepherd Conservation Society, an organization committed to surfacing inhumane acts against whales has also released videos and pictures showing three minke whales that are dead. The dead animals were on the factory ship called Nisshin Maru. Staff of Sea Shepherd believes that a fourth minke whale was being slaughtered just as their helicopter was flying overhead.

The anti-whaling activists released the names of the Japanese vessels believed to be involved in the slaughtering of the whales.

Sea Shepherd Chairman Bob Brown said that when they first spotted the Nisshin Maru, the ship was within New Zealand's territorial waters and it was also on the territory near the Southern Ocean Whale Sanctuary and Antarctica's Ross Dependency. The Japanese vessel has no legal rights to be on these international waters. Brown described it to Discovery.com as a "gross breach of international law."'

Since 1994, the International Whaling Commission has prohibited the hunting of whales for commercial purposes. However, some agencies in Japan still hunts for whales, citing a loophole in the moratorium which allows hunting for whales for research purposes.

"There is nothing scientific about this, it is butchery, the one thing that's missing here is gumption -- a bit of spine in Canberra and in Wellington to put an end to it," Brown told Discovery.com.

He also described the violence that he saw being inflicted on the whales, saying that the hunters were using grenade-tipped harpoons to be able to catch them. Brown said that Sea Shepherd is acting heavily on this matter.

Sea Shepherd has also called for New Zealand and Australia to take action regarding the issue.

However, Foreign Minister Murray McCully of New Zealand denied allegations of whaling that took place within their country's maritime territory. McCully reasoned that the site for the alleged slaughter of the whales was international waters, and they had no jurisdiction over it.

"The New Zealand government has repeatedly called on Japan to end its whaling programme. We reiterate this message today," McCully said to Discovery.com.

Japan's fisheries agency also denied the claims, adding, "We are not aware of the existence of a whaling sanctuary so we don't want to comment on their arguments."