More pressure is needed from Beijing to prod Manila to respond to the demands of the 2010 bus shooting survivors and victims' families, but experts say Beijing is reluctant to act out of fear of worsening relations.
Today marks three years since sacked policeman Rolando Mendoza shot dead seven Hong Kong tourists and their guide on a hijacked bus before being shot dead in a bungled rescue in Manila's Rizal Park.
The Philippine government was roundly criticised over police officers' handling of the situation and some held it responsible for the failed rescue bid.
Survivors and families of the victims have requested a formal apology and compensation from Manila, punishment for the officials responsible and improved tourist safety. They rejected an apology on Tuesday from Joseph Estrada, the new mayor of the city, saying it was insincere.
They say that when a Taiwanese fisherman was shot dead by Philippine coastguard crew, Manila apologised in three months.
While this swift response may be in part to do with Taiwan's ties with the United States, which has influence over the Philippines, experts say Beijing could do more in the bus shootings case.
President Benigno Aquino declared a day of mourning and ordered all flags be lowered to half-mast after the tragedy. The government later allowed Hong Kong investigators to gather evidence in Manila. These actions were both likely to have been the result of pressure from Beijing, said both Professor Simon Shen Xu-hui, of Chinese University, and veteran China watcher Johnny Lau Yui-siu.
But Lau said more pressure could be applied. "There is a lot Beijing can do. For example, it could restrict trade between the two countries and limit tours to the Philippines. That could inflict some real pain there, but whether it's willing to do this or not is another matter," he said.
Relations between the two countries are strained by the South China Sea dispute, and the Philippines has traditionally had close ties with the US. "Beijing will not want to damage its relationship with Manila further over the hostage incident. That would only make the Philippines lean even closer towards the US," Lau said. He added that the US must have exerted a lot of pressure on Manila to extract such a fast apology for Taiwan.
It's a view shared by Dr Richard Hu Weixing, an associate professor at the University of Hong Kong. "Washington didn't want to see a deteriorating relationship between Taipei and Manila, its two de facto allies in the region. It wanted the issue resolved as quickly as possible," Hu said, adding that tough sanctions from Taipei - including a ban on hiring new Filipino workers - also played a part. Hu's colleague Dr Yvonne Chiu, who specialises in international justice, said that as a Chinese city, it was harder for Hong Kong to negotiate directly with Manila. The nature of the two incidents was also at play. "The Taiwan incident is a political problem at base, because it happened because of territorial claims, while the Hong Kong incident was more a criminal one."
After the tragedy, Hong Kong issued a black travel alert, advising travellers to avoid the country. Secretary for Security Lai Tung-kwok said yesterday that the travel warning would remain.
"The situation since the hostage incident has not substantially changed, and we do not consider that it is an appropriate time to lift this alert," he said, adding the government would continue to pursue the case with Manila.
Tse Chi-kin, whose brother, Masa Tse Ting-chunn, was killed in the tragedy, said Chief Executive Leung Chun-ying had not been as active in seeking justice from Manila as his predecessor, Donald Tsang Yam-kuen. "We are looking for concrete moves to support his promises," he said. They would seek help from Beijing when they ran out of options in Hong Kong, he said.