WELLINGTON: New Zealand and Australia said today they would investigate a Japanese whaling ship's alleged ramming of a protest boat in Antarctic waters, as activists claimed only luck prevented someone being killed.

The two countries, opponents of Japan's whaling programme, also urged protesters from the militant Sea Shepherd anti-whaling organisation and the whalers to stop risking human lives in the isolated Southern Ocean. The whalers and Sea Shepherd protesters blame each other for yesterday's collision, which ended with the six crew members on the Ady Gil being rescued by another protest vessel.

New Zealand Foreign Minister Murray McCully said the country's maritime authorities had responsibility for the New Zealand-registered Ady Gil, a hi-tech trimaran which had its bow demolished in the collision with the Shonan Maru No. 2. Separately, Australian Deputy Prime Minister Julia Gillard ordered the Australian Maritime Safety Authority to probe the incident, which occurred in Australia's area of responsibility for search and rescue.

Japan has complained to Wellington about the collision involving the New Zealand-registered protest boat, top government spokesman, Chief Cabinet Secretary Hirofumi Hirano, said in Tokyo.

Sea Shepherd chief Paul Watson said his organisation would continue harassing the Japanese whaling fleet despite the setback. “It handicaps us, it's a two million dollar hit on our organisation, plus it takes away our fast interceptor vessel but this is a war,” he said.

Glenwood Inwood, a New Zealand-based spokesman for the Japanese Institute of Cetacean Research, which conducts the whaling, said the protesters were to blame.

Referring to calls by Australia and New Zealand for an easing of the confrontation, Inwood said the whaling vessels were already acting with restraint.