Three Irish people are onboard a Greenpeace ship which has located a Japanese whaling fleet in the Southern Ocean and is pursuing it.
'If they stop to whale, then we will intervene,' Greenpeace Australia chief executive Steve Shallhorn said.
He said the Japanese fleet of six would be prevented from whaling while it was being followed by the Greenpeace ship, the Esperanza.
Japan's whaling fleet plans to hunt 935 minke whales and 50 fin whales for research over the Antarctic summer, but recently abandoned plans to hunt 50 humpback whales after international condemnation and a formal diplomatic protest by 31 nations.
Greenpeace has been searching for the whalers for 10 days and found the fleet in the early hours of today by following krill, which the whales eat.
Greenpeace said on its website that activists plan to put inflatable boats between the whalers' harpoons and the whales if the fleet begins whaling.
Japan has long resisted pressure to stop scientific whaling, insisting whaling is a cherished cultural tradition. Its fleet has killed 7,000 Antarctic minkes over the last 20 years.
