By Helen Briggs
BBC News science reporter
Greenpeace activists are occupying the site of a proposed whale meat factory in Ulsan, South Korea, ahead of talks on the state of the world's whale stocks.
South Korea intends to build a whale research centre on the site
Environmentalists fear the International Whaling Commission (IWC) will sanction a return to commercial whaling at its annual meeting, which starts this week.
Under an international agreement there is a moratorium on the hunting of whales, but some can be killed for scientific research.
The whaling nations - Norway, Iceland and Japan - and their opponents, are bitterly divided on the issue of whether stocks of some species have recovered enough during the 19-year ban to make hunting sustainable.
The Whale and Dolphin Conservation Society is one of many conservation groups fighting plans to allow hunts limited by quotas which will be discussed in Ulsan.
The society's whaling expert Sue Fisher says the commission should be focusing on making the moratorium work - "not trying to create a management model that the whaling nations have no intention of complying with; with loopholes so big you could drive a blue whale through them".
The whale hunting nations have fought to overturn the moratorium on commercial hunting since it was imposed in 1986.
Norway has continued to kill minke whales in the North Atlantic since 1993 through a legal objection lodged against the moratorium. Japan and Iceland also continue to kill whales, for so-called "scientific purposes".
Environmentalists oppose plans for regulated hunting
The governments that make up the IWC agreed to begin drawing up rules for the quota system at last year's meeting in Sorrento, Italy.
At the heart of the proposals, to be discussed in Ulsan, is a scheme to model how many whales can be killed without damaging overall numbers - the Revised Management System (RMS).
But some marine biologists say whale stocks are still low and too little is known about pre-industrial whale populations to make hunting safe.
They are worried that if the quota system were adopted it could lead to renewed overexploitation of whales.
"The RMS is not only fundamentally flawed, it is not enough," Sue Fisher told the BBC News website.
"Alone the RMS cannot bring whaling back under control. Japan, and any other country that so chooses, will still be able to conduct scientific whaling and take as many whales as they want, entirely outside the control of the IWC.
"That isn't responsible management; it's a complete abdication of the world's responsibility to conserve whales."
In Ulsan itself, opinion is divided over a return to whaling. Many locals can remember eating whale meat as a child when it was a staple part of the diet and say a whaling revival would boost the local economy.
South Korea joined the 1986 moratorium on whaling but makes an exception for whales accidentally killed in fishing nets. The whales can be butchered and legally consumed after police have inspected the carcasses to make sure there is no sign of foul play.
But environmentalists fear South Korea will vote with pro-whaling nations on measures that would weaken the moratorium.
They say that for the first time since commercial whaling was banned, pro-whaling countries may hold the majority of votes due to the growing number of developing countries that have recently joined the commission.
It raises the possibility that the commission might pass resolutions supporting Japan's scientific whaling programme, or the resumption of limited kills.
Jun Koda, councillor in charge of fisheries at the Japanese Embassy in London, UK, said he hoped the scheme to allow limited kills would be passed at the meeting.
"From our point of view the RMS is one of the steps to resuming commercial whaling," he told the BBC News website.
"Whale eating is a tradition continuing for more than 4,000 years so that is part of our traditions and we think each country should respect each other and other cultures."
And the IWMC - World Conservation Trust, a group that promotes "the sustainable use of wild resources" was scathing of Greenpeace's latest action in Ulsan, calling it "tiresome".
"Greenpeace of course claims that [South Korean accidental catches] are purposeful and that they are a dishonest fact of life in South Korea," the IWMC said in its latest newsletter this weekend.
"Another perspective is that there are so many minke whales off Korea's coasts that they are commonly entangled, as they are in the waters off Japan, and that it would be wasteful to refrain from using them.
"Korean people have their own long-standing culinary traditions in whale consumption that are unique to this peninsular nation. They are not about to give them up because foreigners demonstrate their intolerance towards them."
But Greenpeace hit back: "Korea has accidental bycatch rates almost 100 times higher than nations that do not have a whale meat trade.
"It does not take a genius to see that, in a country where dead whales are worth up to $100,000, the building of a whale meat processing factory will encourage the deliberate targeting and illegal hunting of Korea's disappearing whales."