More than 1,000 tour groups from Hong Kong and the mainland have canceled trips to the Philippines after a deadly bus hijacking in Manila on Aug 23, a senior Philippine official said.

The cancellation of trips has resulted in an economic loss of more than US$200,000 to the Philippine tourism industry, which is expected to sustain losses of more than US$500,000 over the next three months, according to Simeon P. Marfori, undersecretary of the Department of Philippine Tourism, who spoke at an annual forum on international tourism, which ended on Friday in Guilin of South China's Guangxi Zhuang autonomous region.

In the siege two weeks ago, a sacked police inspector hijacked a bus full of Hong Kong tourists in a crazed bid to regain his former job.

The standoff ended in bloodshed, when unprepared police commandos launched a flawed rescue attempt that left eight tourists dead.

"Usually at this time of the year, with the National Day holiday approaching, tours to the Philippines are very popular", said Wang Yan, a travel agent in Shanghai. "But we have recently cancelled most tour groups, because our customers are concerned about security in the country."

In Chengdu, capital of Southwest China's Sichuan province, all tours to the Philippines in September and over the National Day holiday - a week-long vacation that starts on Oct 1 - have also been cancelled, according to local media.

Marfori said the Philippine government had taken a series of measures since the hijacking, including training local security forces to ensure the safety of tourists.

He said Hong Kong tourists now account for about 10 percent of all inbound tourists to the Philippines, as well as that the annual growth rate of Chinese tourists to the country tops all other markets.

Marfori asked for forgiveness from the Chinese people. "I sincerely hope the Chinese people, especially Hong Kong people, will accept our apology," he said.

Experts urged the Philippines to raise awareness of the crisis in the industry and to improve the quality of services and security, as cross-border travel becomes increasingly popular.

"It's necessary for every country to improve the quality of its tourism," said Kaye Chon, a professor of hotel and tourism management at Hong Kong Polytechnic University. "The quality of tourism includes not only services, but also security."

Haiyan Song, another professor at the same the university, speculated that the hijacking will cast a shadow over Hong Kong for the next three to five years.