Prosecutors said on Tuesday that they were considering laying a more serious charge against the bus driver involved in the fatal Tai Po accident at the weekend, as he appeared in Fanling Magistracy accused of dangerous driving causing death.
Nineteen bus passengers were killed in Saturday's accident and more than 60 were injured.
The driver of the KMB double-decker, Chan Ho-ming, was denied bail at his court appearance, with the magistrate saying the case was "too serious".
The court was told that Chan, 30, is suspected to have been driving at 70 km/h down a slope when the bus toppled over at a bend in the road.
KMB had said Chan was only working part-time and in court his occupation was given as "cook".
A prosecutor said police officers had yet to take statements from more than 30 passengers and potential eyewitnesses.
She also told the magistrate that autopsy reports were not ready and investigators needed more time to examine the wreckage of the bus and analyse the vehicle's tachograph, commonly known as a "black box".
The prosecutor said further legal advice would be sought on whether the current charge against Chan was suitable.
He was due to appear in court again on April 10.