Hong Kong's new electronic auto-toll system was off to a smooth start at the Western Harbour Crossing, where it launched on Sunday at 5am.

Under the HKeToll system, drivers no longer need to stop at toll gates to pay tunnel fees.

Writing on her social media page, transport commissioner Rosanna Law said the transition went smoothly and thanked other government departments for their assistance.

This is the second harbour crossing in the city to use the electronic toll system, after the Cross-Harbour Tunnel.

The system will be further extended to the Eastern Harbour Crossing on August 27.