South Korea's plan to resume hunting whales for research purposes has drawn immediate protests from non-whaling nations and environment groups that suspect the plans may be a cover for commercial whaling.

South Korean officials announced the plan to the International Whaling Commission (IWC) during an IWC meeting this week in Panama, according to Seoul's Ministry for Food, Agriculture, Forestry and Fisheries.

The whaling would be aimed only at studying the types and amounts of fish whales eat because fishermen complain that an increasing number of whales are consuming large amounts of fish stocks, ministry officials said Thursday.

The IWC gives member states sovereign rights to scientific whaling but South Korea will still give up its whaling plans if the international organisation rejects them, the officials said on condition of anonymity because they were not authorised to speak to media.

Environmental groups decried the South Korean plan as a back-door effort to make the country only the fourth to allow commercial whaling, which has been banned since 1986. Various exceptions have allowed Japan, Iceland and Norway to hunt whales anyway. Indigenous groups in several countries also hunt whales as allowed under international rules.

On Friday, a small group of South Korean activists staged a performance in Seoul to protest against their government's announcement. They dressed like whale researchers and pretended to slash a mock-up of a baby whale with a chain saw and pound it with a hammer. Laid in front of the mock-up were two cardboard crosses that showed the flags of South Korea and Japan.

Japan claims its hunts are for research purposes, though the meat from the killed whales mostly ends up in restaurants, stores and school lunches. South Korean officials said they haven't determined what to do with the whale meat after the studies.

The leaders of Australia and New Zealand quickly condemned South Korea's plans and said they would raise diplomatic protests. Even close ally the United States chimed in with criticism.

"We think it would be a terrible step in the wrong direction," New Zealand prime minister, John Key, said during a visit to Sydney.

Australian prime minister, Julia Gillard, told a news conference that she was "very disappointed" at the South Korean announcement.

"We are completely opposed to whaling, there's no excuse for scientific whaling," she said.

Wendy Elliott, head of the global environmental group WWF's delegation to IWC said they believed the move was "a thinly veiled attempt by Korea to conduct commercial whaling under the guise of scientific research, similar to hunts conducted by Japan."

US State Department spokesman Patrick Ventrell said Washington remained committed to the moratorium on commercial whaling.

"We're concerned about South Korea's announcement that it will begin a lethal scientific research whaling programme, and we plan to discuss this with the South Korean government," Ventrell told reporters in Washington.

South Korea still outlaws whaling for commercial purposes under the 1986 ban. The country briefly conducted a scientific hunt of mink whales in 1986 and it hunted three to four dolphins for similar purposes annually between 2004 and 2010, according to the South Korean fisheries ministry.