New Zealand said Friday it would join an Australian attempt to stop Japanese whaling through the courts after failing to persuade Tokyo to halt its annual cull through diplomatic channels.
Foreign Minister Murray McCully said New Zealand had formally applied to join Australia's action in the International Court of Justice, which challenges the basis of Japan's "scientific" whaling hunt.
McCully said he was disappointed diplomatic initiatives had failed to halt Japanese whaling in the Southern Ocean, which Australia and New Zealand argue is needless and has no scientific merit.
"New Zealand has worked hard with Japan for over three years to try and find a permanent solution to whaling in the Southern Ocean," he said in a statement.
"The government will continue to use all avenues possible to try to bring a halt to Japanese whaling in the Southern Ocean."
Australia launched its legal action in December 2010 but New Zealand concentrated its efforts on trying to persuade Japan to voluntarily drop whaling.
Commercial whaling is banned under an international treaty but Japan has since 1987 used a loophole allowing the marine mammals to be harpooned for scientific purposes.
The Japanese fleet aimed to cull about 900 whales in the 2011-12 season but took less than a third of its intended haul due to environmental groups such as Sea Shepherd, which dog its activities on the high seas.
Japan's Fisheries Agency said in September that it planned to refit the fleet's factory ship, which is pivotal to the operation, in the hope of getting at least another decade's service.
Explore further: Japan eyes at least 10 years whaling with ship refit