Hong Kong's new electronic auto-toll system went into operation at the busy Cross-Harbour Tunnel on Sunday.

HKeToll, which was already up and running at a number of other tunnels, eliminates the need for drivers to stop at booths to pay fees. The tolls are automatically deducted for motorists with a registered electronic tag in their vehicle, while others will be sent a bill.

Signs were put at the crossing between Hung Hom and Causeway Bay, advising drivers not to stop to pay.

However, some appeared confused, slowing down as they approached the former toll booths.

Some taxi drivers told RTHK they think HKeToll will help ease jams at the tunnel.

But a driver surnamed Chan said there are some issues with the new system.

"It’s a bit confusing. Sometimes the system can’t detect the e-toll vehicle tag when the taxi passes through, which affects us," he told RTHK.

"If the system can’t detect the tag and collect the charge, I have to ask the taxi owner to pay it. If they fail to pay it, there’ll be a penalty."

A taxi driver surnamed Lam agreed there are some difficulties with the new arrangements.

“The HKeToll app is still not easy to use. Sometimes when we need to check the overdue amount, there are some problems,” he said.

Another driver said that although things went smoothly on Sunday, there could be problems on Monday now that the number of lanes at the tunnel entrances have been cut in half.

Transport Commissioner Rosanna Law said Monday morning's rush hour would indeed be the real test.

The government plans to extend the e-toll system to the two other cross-harbour tunnels next month.