The labour importation scheme is being strangled by red tape, threatening the 1998 opening of the new airport and associated railway, according to the Airport Authority and the Mass Transit Railway Corp (MTRC).
They say bureaucracy has caused a shortage of skilled workers in the territory.
The authority and MTRC have urged the Government to overhaul the labour importation scheme to speed up visa processing.
Both have met officials at the New Airport Projects Co-ordination Office (Napco), the Government agency overseeing the airport core programme, to seek ways to speed up procedures.
Napco confirmed there was deep concern and had agreed with the Education and Manpower branch on a number of improvements.
'As a result the standard [visa] processing time has been reduced from four months to about three months,' Napco spokesman Helima Guterres said.
'This three-month period includes four weeks for advertising vacancies at labour department and airport core programme job centres.' Contractors said the problem would come to a head in the next six months when 15,000 to 20,000 workers would be needed to install air-conditioning, electrical and other systems.
They would be concentrated in the passenger terminal and along the 34 km airport railway, especially at the five stations in Central, Kowloon, Tai Kok Tsui, Lai King and Tung Chung.
One senior construction manager said: 'The crunch will come at the end of this year and continue into next.' Most of these craftsmen would be brought in from China, the Philippines and Thailand, but contractors said the present system was so cumbersome they doubted if so many visa applications could be processed in time.
A contracts manager at a railway contractor said: 'Obtaining visas under the scheme can take months - but we don't have months. The MTRC is very worried. They can see a trend developing before the contractors.' Firms said it could take up to six months from the initial application before workers arrived on site.
The issue has been taken up by the Hong Kong Electrical and Mechanical Contractors Association, which has held meetings to help resolve the problem.
The association said there was another meeting in a few days.
The Airport Authority's corporate development director, Clinton Leeks, welcomed the apparent improvements but said it would continue to press for ways to enhance the importation scheme.
'Our job is to get the airport completed on time, within budget, and to ensure our contractors meet their obligations,' he said.
'We are not looking for radical surgery, but contractors are entitled to expect they can get labour quickly and fairly.'