Hong Kong has one of the most dependable electricity supplies in the world, with a reliability index of almost 100% for the last three years.

Responding to enquiries on yesterday's power failures in the eastern part of the US and Canada, the Economic Development & Labour Bureau said Hong Kong's two power companies have sophisticated systems that minimise the risk of major supply interruption and deal with any emergency situation.

The Electrical & Mechanical Services Department regularly monitors power supplies for compliance with the best operational and engineering practices.

The bureau said the reserve capacity margins operated by both companies are sufficient to ensure the public continues to receive power should there be an unexpected outage of individual generating units.

In addition, many key installations in institutions such as health care, banking and public transport, including the airport, have a back-up supply installed.