Ten Vietnamese picked up in waters off Chek Lap Kok were said to have been headed towards home on a raft made of debris from the new airport site.
Police intercepted the five-square-metre raft about 1.5 kilometres southwest of Chek Lap Kok on Tuesday night. They said the crew, aged 18 to 54, had been working illegally on the airport site.
The sailors had equipped themselves with just three bottles of water, small tools, 11,000 yuan (HK$10,300), $3,000 and some photos. None had luggage.
Marine West divisional commander Superintendent Ling Wai-po said materials used to build the raft - which had handrails and two home-made engines - were believed to have been scavenged from Chek Lap Kok.
'It appears the bamboo poles were dismantled from scaffolding and the two engines are made up of two converted road rollers and home-made propellers,' Mr Ling said. The result was 'creative', but he doubted it could have withstood heavy seas.
'Outside Hong Kong waters, they would have been picked up by another boat, which would take them to China before returning to Vietnam,' he said.