The coroner has ordered autopsies on the hijack victims as well as a police investigation, raising the possibility of an inquest into the killings.
Secretary for Security Ambrose Lee Siu-kwong told a special meeting of the Legislative Council's panel on security that the coroner will make a decision on whether to call for an inquest based on the results of the autopsies and the police probe.
He said he expected the autopsies to be completed in 24 hours.
Last night, a spokesman for the Judiciary said: "The coroner has decided that an investigation into the deaths by the police should be carried out, taking into account all relevant considerations in accordance with the law.
"The coroner also ordered autopsies on the bodies."
However, Lee cast doubts on calls from lawmakers to press for a joint probe into the hostage-taking incident with Philippine authorities - even with SAR officials acting as observers.
Lee said he had been told by mainland authorities a joint probe would be very difficult to realize as the Philippines has its own sovereign laws.
Lee said there are also no precedents for a joint investigation.
But he disclosed that police officers, including forensic experts and those from the Organized Crime and Triad Bureau who flew to Manila on Tuesday, had received some information from the Philippine police about the case.
He also said a Hong Kong pathologist had observed the autopsies on two bodies in the Philippines and only observed the wounds on three other bodies as the autopsies by Philippine pathologists had been completed by the time he arrived.
No autopsy was carried out on the three other bodies in Manila as per the request of their families.
After the panel meeting, Lee disclosed police officers had been to Manila to interview some survivors. But he declined to give further details as this might affect a possible inquest.
Lee said the Hong Kong government had demanded the Philippines carry out a "comprehensive, just and professional investigation" into the incident.
He also said the black outbound travel alert will be maintained until the risk of traveling to the Philippines has been reduced.
Many lawmakers said they had no confidence in the credibility of the Philippine investigation and in a report which consul general Claro Cristobal said will be ready in the next few days.
Democrat legislator James To Kun-sun questioned how it could be done so quickly when there are so many witnesses and police officers to be interviewed.
Lawmaker Paul Tse Wai-chun described the hurried probe as "ridiculous."