South Korea is under fire from governments, including New Zealand, and environmentalists about its plan to resume hunting whales under a "scientific" research programme.
South Korea told a meeting of the International Whaling Commission (IWC) in Panama City it intends to begin a scientific whaling programme in the north-west Pacific.
It said whaling is a longstanding cultural tradition.
Prime Minister John Key described the move as a terrible step in the wrong direction.
"It's a terrible step in the wrong direction. We think it's unnecessary, we think it's inappropriate and we don't think the stocks would support that," Key told reporters in Sydney where he attended a business lunch.
"Most people around the world would be disappointed if the Koreans took this step."
Foreign Minister Murray McCully said the so-called scientific move will have no more credibility than a similar programme by Japan.
"In this day and age there is simply no need to kill whales in order to conduct effective research," McCully said.
Key said the move had taken him by surprise and he had no official warning.
"The government will be putting the issue up during talks with Korean officials," he said.
"Our ambassador in Korea will be taking our position up with foreign officials there, and our foreign minister Murray McCully will be talking to the Korean foreign minister when he sees him next week."
Both Labour and the Greens have supported the Government's objection to the South Korea proposal at the IWC meeting.
"The hunting of whales is no more 'scientific' than is any other blood sport," said Labour's conservation spokesperson Ruth Dyson.
"The global community has no taste for whale slaughter. And let's not pussy-foot around - that is what this is."
Green Party co-leader Metiria Turei expressed outrage at Korea's intention to exploit the loophole in the IWC 1986 moratorium on commercial whaling.
"It is clear that Korea will use any excuse to hunt whale," said Turei.
South Korea said its fishermen claim growing whale populations are depleting fishing stocks. But critics said the move was modelled on Japan's introduction of scientific whaling after a 1986 moratorium on commercial whaling.
Japan argues it has a right to monitor the whales' impact on its fishing industry.
"We are worried about this proposal because it goes against the ban ... we don't support whale hunting under any circumstances," said Tomas Guardia, Panama's representative to the international body.
World Wildlife Fund said South Korea's fishing assertion has no scientific basis.
Environmental activists say the term scientific whaling is a thinly veiled ruse to allow hunting in countries where whale meat is a popular delicacy.
"It's an absolute shock this happened at this meeting and it's an absolute disgrace because to say that hunting whales is happening in the name of science is just wrong. Essentially, it's commercial whaling in another form," James Lorenz from Greenpeace told Australian television.
Lorenz said South Korea must take its proposal to the Whaling Commission's science committee.
Many Koreans view whale meat as a delicacy. Murals some 5000 years old depicting whaling have been excavated around Ulsan, centre of the whaling industry on the southeastern coast since the late 19th century.
Officials say that before South Korea joined the moratorium in 1986, its average annual catch was 600 whales, most of which was consumed.
Whaling is now subject to prosecution and punishable by a jail or fines, but meat is available from mostly minke that get caught in fishing nets "by accident" or wash ashore.
The minke whales that South Korea proposes hunting are considered endangered, the World Wildlife Fund said in a statement.
Aussie MPs condemn plans
The Australian federal government said they remain "absolutely opposed" to whale hunts disguised as scientific programmes, with Prime Minister Julia Gillard saying she would fight the proposal.
Gillard said it would lodge a diplomatic protest against South Korea's move.
"We will make our voices heard today," she told reporters.
"Our ambassador will speak to counterparts in South Korea at the highest levels of the South Korea government and indicate Australia's opposition to this decision."
Australia has filed a complaint against Japan at the International Court of Justice in The Hague to stop scientific whaling. A decision is expected in 2013 or later.
Australian Deputy Prime Minister Wayne Swan said more information was needed on the South Korean stance but signalled Australia would not support such a move.
"This government is absolutely opposed to commercial whaling," he told reporters in Brisbane.
"And we are absolutely opposed to any arrangement that might seek to disguise commercial whaling as scientific whaling."
Coalition leader Tony Abbott said he would respectfully tell the South Koreans "don't do it".
"We oppose whaling," he told reporters in Somersby, NSW.
Twitter was awash with condemnations.
"I don't care what justification you give," wrote a user identifying herself as Savannah, from Australia. "It's crap. Stop killing whales."
- with AAP and Reuters