Whether the Tai Lam Tunnel should be free at certain times was up for debate among lawmakers on Friday, with the government expressing reservations about the suggestion.

Most legislators agreed, however, that the administration should charge time-varying tolls after it takes control of the New Territories tunnel next year.

In documents submitted to the legislature earlier, officials outlined three different pricing scenarios, including two fixed toll proposals and a third with different fares for peak, regular and off-peak hours.

Under the proposed staggered tolls, private car drivers would pay HK$45, HK$35 or HK$20 depending on the time of day. Taxi drivers would pay HK$30 at all times, while commercial vehicles would be charged HK$45.

Liu Chun-san, the undersecretary for transport and logistics, said the government has reservations about making the tunnel free.

"The reduction is not acceptable for the point of view of the use of public money and traffic management. We have to make sure that the traffic is smooth, and to maintain the tunnel, we need to charge a toll," Liu said.

Some lawmakers, including New People’s Party chairwoman Regina Ip, said they believe fees are necessary.

"We have to let people know the infrastructure is a massive public investment and we should make the best use and do not abuse any infrastructure. We have to let people know that resources are valuable. So I'm against an infrastructure service free of charge," Ip said.

But Edward Lau of the DAB said he would not support any of the three pricing scenarios put forward by the administration.

"For the new tunnels... all of these are offered for use free of charge. Why do you adopt a different principle for the Tai Lam Tunnel?" Lau asked.