Children under eight travelling in private cars will need to be in a safety seat or strapped in with some other child restraining device (CRD) from November 1, transport officials said on Monday.

The only exception to the new rule will be for those children who are at least 1.35 metres tall.

As well as child car seats, drivers can also secure their young passengers with seat belt adjusters, wearable safety restraint vests or foldable boosters.

People caught flouting the regulation will risk a fine of HK$230, while "serious cases" could lead to court action and penalties as high as HK$2,000.

The Transport Department noted that drivers who break the rule might be able to avoid punishment in emergency situations, for example if they didn't have time to put the child in a restraining device because they needed to drive them to hospital urgently.

"The new requirement aims to enhance protection for children and passenger safety. CRDs provide effective protection for child passengers in traffic accidents and they can substantially reduce the risks of being killed or seriously injured," a department spokesperson said.

Officials noted that children not covered by the new regulation will still need to be strapped in, either with a restraining device or with a normal adult seat belt.