Japan confirmed today that it will press ahead with an expanded annual whale hunt that will for the first time target humpback whales, internationally listed as a vulnerable species.

Japanese whalers plan to kill more than 1,000 whales in the Antarctic Ocean on an annual mission that has long caused tension with New Zealand and Australia – which could send military aircraft to monitor the hunt if there is a change of government after elections next week.

Japan’s Fisheries Agency said its fleet would go ahead with the expedition but said the date will only be announced shortly before for security reasons. “We will go ahead on the day that we planned,” said an official from the whaling division. The fleet usually leaves in November.

The environmental group Greenpeace has accused Japan of delaying this year's hunt because Yasuo Fukuda, the Prime Minister, does not want unwelcome publicity during his current trip to the United States.

The whaling programme “is a sham and a source of diplomatic tension between Japan and countries that support whale conservation, like the United States,” said Karli Thomas, leader of Greenpeace’s Esperanza which will try to track the whalers.

“Prime Minister Fukuda should not just delay the whaling fleet’s departure to avoid political embarrassment abroad, he should cancel Japan’s entire whaling programme and decommission the vessels to end the domestic scandal of wasting Japanese taxpayers’ money,” Ms Thomas said in a statement.

Japan has used a loophole in the two-decade international moratorium on commercial whaling that allows the killing of whales for research – although it makes no secret that the meat ends up on Japanese dinner plates. This year, for the first time, it plans to kill 50 humpbacks and 50 fin whales, as well as hundreds of minke whales, arguing that levels of both whales have recovered enough to allow them to withstand hunting.

Australia’s opposition Labor Party said yesterday that it would use military aircraft to monitor the hunt and gather evidence for a legal challenge against the practice if, as widely expected, it wins national elections on November 24. Japan does not recognise the Australian-declared whale sanctuary in the Southern Ocean.

Labor's foreign affairs spokesman, Robert McClelland, said that the military surveillance would help support a bid to convince an international tribunal to ban the annual slaughter.

“We are going to use ... military resources to monitor the activities of the whaling vessels,” Mr McClelland told reporters. “What is important is getting evidence ... as to what’s going on and getting the facts that can actually be presented to an international tribunal to try to get rulings to stop this,” he added.

The military surveillance could occur within weeks, as the Japanese fleet plans to soon begin its annual commercial slaughter of hundreds of whales in Antarctic waters.

Labor argues that Australia could take action against the whalers in the International Court of Justice in The Hague or the International Tribunal of the Law of the Sea in Hamburg to add to international pressure against whaling.

But Alexander Downer, the Australian Foreign Minister, described Mr McClelland’s announcement as a political stunt aimed at winning the election. “It shows a complete lack of understanding of the legal status of Antarctica,” he said.

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