MANILA - The Philippine government said it was delaying a high-level diplomatic mission to Hong Kong and China to explain the handling of a deadly hostage crisis until an investigation into the event was completed.

Foreign Affairs Secretary Alberto Romulo and Vice President Jejomar Binay are due to lead the delegation but no date has yet been fixed, the Department of Foreign Affairs said in a statement released on Thursday night.

"While the delegation is ready to leave anytime, there is an understanding between both sides that the Philippine delegation will bring a full report of Monday's incident," the statement said.

"Concerned Philippine authorities are now conducting a proper investigation with a view to completing the report as soon as possible."

The Philippine government had indicated earlier it intended the delegation to depart for Beijing and Hong Kong as soon as possible, and had not mentioned that it would need to wait for the final results of the investigation.

An ex-policeman armed with an assault rifle hijacked a busload of Hong Kong tourists in Manila on Monday as part of a bid to get his job back and have himself cleared of extortion charges.

Eight of the tourists and the gunman were killed in the final stages of the 12-hour ordeal, when ill-equipped and poorly trained police launched an assault on the bus as the events were broadcast around the world live on television.

The Philippine government and police have admitted to making many mistakes in the handling the crisis, which has caused widespread anger in Hong Kong.

Philippine police said on Thursday they could not yet determine whether the bullets that killed the eight tourists came from their weapons or the gunman's.

The government's inquiry involves the justice and interior departments, while the police are conducting their own probe and the Senate is also conducting hearings into the affair.

The government has not said when its investigation will be completed.