The 10-meter mammal - first seen by Marine Police off Lamma Island on Monday - was spotted again yesterday off Stanley.

"Humpbacks are usually found in the western Pacific," said Ocean Park general curator Grant Abel. "They can also be spotted east of Taiwan but this is the first time a member of its species has appeared in Hong Kong. It is definitely out of its normal range."

Abel said the territory's biggest visitor could have been injured, stranded or left behind by its pod and unable to reestablish contact, adding its movements suggested it was confused.

Hong Kong Cetacean Research Project director and current Hong Kong Dolphin Conservation Society chairman Samuel Hung Ka-yiu said he has been tracking the whale since its first sighting.

"It has been hanging around the same area, making its way a little bit to the east," he said. "It seems it does not know how to get out of Hong Kong, but it may find its way out in time."

Hung said the humpback should be heading toward its Arctic feeding grounds from its tropical breeding grounds at this time of year.

While whales are accustomed to long journeys without food, the city's waters lack a suitable food source, Hung said. The longer it stays in Hong Kong waters the greater the risk.

The whale has proved evasive to attempts by Hung and the Agriculture, Fisheries and Conservation Department to get close to it.

"We recommend the government refrain from doing anything outside of monitoring the animal," Hung added. "There's no real way to lure it out into the ocean other than trying to scare it, but that would raise its stress levels, making it aggressive and increasing the risk it could head to shore and become beached."

Hung appealed to the public to refrain from trying to get close to the whale, after several media outlets swarmed the area.

An AFCD spokeswoman said the whale's condition appears to be good, and the department was keeping a close eye on its progress.

The Marine Department is also broadcasting radio warnings to vessels near the whale to slow down.

In August 2000, a live 12-meter Bryde's Whale was beached at Taipa, Macau and died before AFCD personnel and other experts arrived. On August 19, 2002, a juvenile False Killer Whale was found stranded at Sai Wan in Sai Kung but died the following day.