But its rich scent caught his attention and that of curious bystanders when he docked at the Shau Kei Wan fish market the next day. There were many suggestions that it could be the prized wood, which is protected by a harvesting ban in most South-East Asian countries.

One expert has already said it is just camphor, another fragrant but much less valuable wood. But Kwok is still waiting for laboratory test results.

Samples are being tested by a private laboratory and the Agriculture, Fisheries and Conservation Department, which collected some of the wood after he reported his find to the police.

"I'm not sure what to expect of it. I don't want to think too much about it. What if I get disappointed?" Kwok said yesterday.

"I'll follow my lawyer's advice and instructions from the government. If they say it belongs to the country then I'll just be a good citizen."

The wood, which he estimates at 600 kilograms, weighed a lot more than his 100 kilogram catch on his first day out after Lunar New Year. If it is top-grade agarwood it could be worth as much as US$18 million but even at the lowest end of the range, US$5,000 a kilogram, it's potentially still enough to make him a Hong Kong dollar millionaire.

"You usually only get scrap wood from the sea. I've never dreamt of getting anything like this, and I've never heard of anything like this either," said the third-generation fisherman who has been in the job since he was just 11 years old.

The fragrant wood comes mainly from mature examples of the Aquilaria species infected by a fungus that attacks just a tiny percentage of the trees.

"We just laughed it off at first; a piece of wood with a scent," said Kwok's sister, May. "But many people have been coming to see it and we worried about our brother's safety, so we have gathered round him."

Kwok said he hoped the results would be available soon because the wood was preventing him from going fishing.