Greenpeace's Esperanza _ which is in the ice-strewn waters of the Southern Ocean to try to interrupt Japan's controversial whale hunt _ is one of few ships near the stricken vessel that is equipped to tow it away from trouble and toward port.

Japanese officials on Thursday rejected the idea of help from anti-whaling groups.

They said the fire may spell the end of this season's whale hunt in Antarctic waters because the stricken ship processes all of the animals caught by the smaller ships in the fleet.

"Whether we can complete the hunt would depend on the extent of damage to the ship," said Hajime Ishikawa, an official at the government-affiliated Institute of Cetacean Research in Tokyo. "But it would be difficult to continue if the ship has to be brought into port, because it is the only vessel able to process" captured whales.

The 8,000-ton Nisshin Maru, crippled by fire, without engines and with its main electrical switchboard destroyed, is lashed to two smaller Japanese about 175 kilometers (100 miles) from Antarctic's biggest penguin rookery at Cape Adare.

New Zealand Conservation Minister Chris Carter on Friday said the Japanese government should use either the Esperanza _ a converted Russian tug _ or a U.S. icebreaker in the area to move the vessel.

"It is imperative the Nisshin Maru is towed further away from the pristine Antarctic coast, the neighboring penguin colony and the perilous ice floes," Carter said. "It's likely we have two days of good weather to move the Nisshin Maru out of Antarctic waters in the safest and most practical way."

The Nisshin Maru is carrying 500,000 liters (132,000 gallons) of heavy oil and 800,000 liters (211,000 gallons) of furnace oil.

In Tokyo, Fisheries Agency official Hideki Moronuki rejected concerns the ship may leak oil.

"There is absolutely no oil leak. Concerns of an oil spill are completely unfounded," he said.

One Japanese crewman is missing, presumed dead. The fire has been put out but the engine was down and smoke has filled much of the vessel, officials said.

Crew on Friday hooked up power cables and fans to the stricken ship from one of the other Japanese whalers to try to clear the dense smoke, and the burned out area on the whale processing deck on the ship remained hot, officials said.

"The fire on board the vessel has been extinguished and it's now a matter of removing the dense smoke from the poorly ventilated area," Institute of Cetacean Research spokesman Glenn Inwood said.

Greenpeace renewed its offer of help.

"We have the capacity and we're on the spot," Greenpeace spokeswoman in New Zealand Cindy Baxter said.

The group's expedition leader aboard Esperanza, Karli Thomas, said Greenpeace had a "moral obligation to act, and there is a legal obligation under the Antarctic Treaty for the Nisshin Maru's owners to accept our help."

Institute Director General, Dr Hiroshi Hatanaka, said the crew was making every effort to search for Kazutaka Makita, 27, missing in the fire.

"Fears that this might turn into some environmental disaster are premature. The vessel is not drifting, its not listing and its not leaking," he said. "The area in which the fire broke out is not located near the fuel holds."

Japan says its annual whale hunts, begun after the International Whaling Commission imposed a global ban on commercial whaling in 1986, are for research.

The fleet planned to hunt up to 945 whales from mid-December to mid-March.

The program is allowed by the IWC, but many environmental groups say the hunts are a pretext to keep Japan's tiny whaling industry alive.