"When I saw the photos, I just felt a bit of a sick feeling as well as a sense of sadness," Environment Minister Peter Garrett said. One image showed what appeared to be the young whale's intestine spilling from an explosive harpoon wound.

"They're calling it science, but really it's killing whales," Garrett said.

The government had initially refused to release images to avoid angering Japan, the country's second biggest trade partner.

Despite a moratorium on whaling, Japan is allowed an annual "scientific" hunt, arguing whaling is a cherished tradition and the hunt is necessary to study whales. Its fleet plans to hunt almost 1,000 minke and fin whales this Antarctic summer.

Australia has sent a fisheries and customs patrol ship to the Southern Ocean to gather photo and video evidence of Japan's scientific whaling for a possible challenge in international legal tribunals.

Home Affairs Minister Bob Debus said the images were "shocking" and added to legal weight against Japan's annual hunt as the Humane Society International urges Canberra to launch a case in the International Tribunal of the Law of the Sea. But in Tokyo, Japan's Fisheries Agency accused Australia of trying to stir public outrage.

"While the foreign ministers of the two countries recently agreed to deal with the whaling issue calmly, it is problematic to release the pictures to fan sentiments," an agency official told Reuters.

"EMOTIONAL PROPAGANDA"

Japan's Institute of Cetacean Research, which carries out the whaling, accused Canberra of misleading the public and said the two whales photographed were unrelated.

"They are not a mother and her calf as claimed," director general Minoru Morimoto said in a statement.

"The government of Australia's photographs and the media reports have created a dangerous emotional propaganda that could cause serious damage to the relationship between our two countries," he said.

In one photo a banner hangs from the back of the factory ship saying it is conducting "legal research under the ICRW (International Convention for the Regulation of Whaling)".

The adult whale and the calf, which experts said was under a year old, were tied at the tail by cables as Japanese crew looked down on Australian customs officers in an orange inflatable boat.

Another photo shows a whale tethered to harpoon lines at the bow of a whaling ship boarded by anti-whalers last month.

Australia's Prime Minister Kevin Rudd has promised a stronger effort to try and stop the cull, although both countries have agreed not to let Canberra's opposition to whaling "influence diplomatic negotiations".