Japan's fisheries minister says Australia's announcement it will start international legal action next week to stop Japanese whaling is "very disappointing".
Canberra said it will submit documents to the International Court of Justice in The Hague early next week, following years of tensions over the annual slaughter in waters near Antarctica.
Fisheries Minister Hirotaka Akamatsu said: "It is very disappointing."
He added that Japan's "research whaling is a programme approved" under the rules of an international moratorium on commercial whaling.
"I want to continue to argue on that basis," he told reporters.
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Abbott calls whaling case a smokescreen
Federal Opposition Leader Tony Abbott labelled the government's decision a "smokescreen" to distract voters from what he calls recent policy failures.
"The coalition strongly opposes so-called `scientific' whaling," Mr Abbott told reporters on Friday in Sydney.
But he added: "Plainly it's a smokescreen for the government's failures."
Asked repeatedly if he supported the move, or if a coalition government would take similar action, he bypassed the issue, saying he would need to see the legal argument behind the government's case.
"All I can do is repeat the principle that we support appropriate and effective action in international tribunals," Mr Abbott said.
Commercial whaling has been banned worldwide since 1986 but Japan justifies its annual hunts as lethal "scientific research", while not hiding the fact that the meat is later sold in shops and restaurants.
Tensions have risen sharply between whaling nations, also including Iceland and Norway, and anti-whaling countries such as Australia in recent months.
Militant environmentalists from the US-based Sea Shepherd Conservation Society in the last whaling season succeeded in reducing the Japanese Antarctic catch to 507 whales, down from Japan's target of up to 935 of the animals, through a sustained campaign of high-seas harassment.
One of the activists, New Zealander Peter Bethune, who boarded a harpoon ship in February, went on trial in Tokyo on Thursday, pleading guilty to several charges including trespass.
The International Whaling Commission, which meets in June in Morocco, is considering a plan to allow whaling nations to hunt the ocean giants openly if they agree to reduce their catch "significantly" over 10 years.
