Airlines are checking passports and visas more closely at check-in counters to ensure passengers are entitled to enter Hong Kong, a representative said. An increase in visitors has resulted in more people attempting to slip through on outdated passports or documents borrowed from family members. Airlines that carry passengers with invalid travel documents face fines of up to $10,000 and the cost of returning the passenger to their home country. 'Financially, it's an incentive for the airlines to ensure that everybody they put on board has proper documentation,' Gilbert Chow Yun-cheung, deputy chairman of the Board of Airline Representatives, said. 'Everybody's operating on a very thin margin and if they can contain the cost they will,' Mr Chow, who is also Hong Kong general manager for Northwest Airlines, said. The number of air passengers refused entry to Hong Kong dropped from 14,008 in 1994 to 10,892 last year, while the number arriving at Kai Tak increased from 12.5 million in 1994 to 13.6 million last year. Immigration Department spokesman Sunny Ho Yiu-sun said an increase in prosecutions against airlines had made them more aware of the importance attached to checking travel documents. There were 123 prosecutions against airlines in 1994 and 151 last year, with fines ranging from $300 to $3,800. Visitors were mainly refused entry because their travel documents were invalid or they did not have a visa for Hong Kong, Mr Ho said. The Immigration Department would not release the names of airlines that had been prosecuted for bringing passengers to Hong Kong without proper travel documents. A breakdown of the nationalities of people refused entry was not kept. Those not allowed to enter the territory are kept in a detention centre at the airport and placed on the first available flight to their homeland. After complaints in 1992 that Immigration Department officials had sometimes compelled airlines to return passengers on fully-booked flights, members of the Airline Operators Committee said they were now being flexible about when they should be flown back.