Operating hours of the 23 automated passenger clearance auto-gates, or e-channels, at Lo Wu control point will be extended from today, the Immigration Department says.

The channels will be open daily from 6.30am to midnight. Hong Kong permanent residents, aged 11 or above, holding smart identity cards can use the e-channels to perform self-service clearance.

Thumbs that are too dry or too moist may affect the scanner's ability to read the thumbprint.

If the thumb is too dry, a wet tissue should be used to dampen it before entering the e-channel. If it is too moist, it should be wiped with a dry tissue.

If a user's thumbprint is unclear, the system will have difficulty reading it. To avoid delay, the user can use a traditional counter for clearance.