Airports in the Asia-Pacific region have swept all five top spots in a survey for the world's five best airports of high-quality of customer service.

China registered a strong presence in the rankings, with Hong Kong International, Beijing Capital International and Shanghai Pudong International Airports taking third, fourth and fifth respectively.

The results are based on a survey conducted by the Airports Council International (ACI), a worldwide association for airports. The winners were announced by the ACI at its Airport Service Quality awards, in Montreal, Canada, this week.

"We applaud the consistent success story of the Asia Pacific airports, which set the bar in service excellence," Angela Gittens, director-general of the ACI, said when announcing the award.

Overall, Seoul's Incheon Airport ranks first for the sixth year running, while Singapore's Changi Airport was second.

China garnered yet another prize, when Shanghai Hongqiao Airport was awarded the Best Improvement Award for Asia-Pacific region, thanks in part to the role it played in hosting visitors to the Shanghai Expo 2010.

The ACI surveyed over 300,000 passengers in 153 airports around the globe, of which 140 airports met the qualification to participate in the awards.

"The top performing airports are those that deliver on the basics first general ambience, cleanliness, check in efficiency, courtesy of staff, clear signage, availability of facilities and comfortable waiting areas," ACI's program director Craig Bradbrook said in a statement.

When customers are satisfied by those criteria, they are more likely to indulge in duty free shopping, spa treatment or samples at the lounge restaurants and bars, Bradbrook said.

Overall, the surveyed airports are getting better, with the ACI saying that customer service ratings have improved by 7.5 percent over a five-year period.