Hong Kong  - A humpback whale separated from a migrating group of the marine mammals was trying to find its way out of busy shipping lanes around Hong Kong, enthralling the former British colony.

The plight of the 10-metre adult whale made television and newspaper headlines in the normally money-obsessed city, providing a welcome distraction from a tide of bleak economic news.

The humpback whale, the first ever seen in Hong Kong waters, is believed to have become separated from a group of whales migrating from the tropical waters where they spend winter to their summertime Arctic feeding grounds.

It was first spotted surfacing, raising its tail and exhaling water through its blow hole Monday and Tuesday in busy shipping lanes close to Hong Kong's landmark Victoria Harbour.

By Wednesday, it had moved to the south of Hong Kong island and appeared to be heading eastward to the usual northerly migration route for whales in the South China Sea.

Experts said they believe once it finds its way into open waters, it should be able to rejoin other whales and continue its route toward the Arctic.

However, boatloads of sightseers with cameras have headed out to try to track the whale since it was first sighted, and an appeal has been issued for people not to sail too close to the lost whale.

There were also concerns that there is a lack of food for the whale in Hong Kong's heavily polluted waters, where fish stocks are critically low, and the whale could weaken if it fails to find its way out soon.

Whale expert Samuel Hung Ha-yiu, head of a research centre on dolphins and porpoises, told the Hong Kong Standard newspaper that trying to guide the mammal toward open waters could be counterproductive.

"We recommend the government refrain from doing anything outside of monitoring the animal," he said, adding that trying to usher it out would "raise its stress levels, making it aggressive and increasing the risk it could head to shore and become beached."

Photographs of the whale, meanwhile, have been sent to experts in the United States, the Philippines and Japan to try to discover from where it has swum to reach Hong Kong waters. (dpa)