Sources said on Monday that the government plans to charge cheaper, time-varying tolls for the Tai Lam Tunnel when it takes control of the infrastructure in May.

The tolling system would be similar to the ones for the three cross-harbour tunnels brought in last year, with three levels of charges for peak, general and non-peak hours.

Currently, private car drivers need to pay HK$58 for using the tunnel connecting Ting Kau with Yuen Long.

Sources said in future, it will be HK$45 for peak, HK$30 for general and HK$18 for non-peak hours.

An across-the-board charge of HK$28 is being mooted for taxis, down from HK$58 at the moment.

And commercial vehicles will pay HK$43, which would be cheaper than current toll levels.

DAB lawmaker Ben Chan, who chairs the Legco transport panel, said he finds HK$45 for private cars during peak hours to be on the high side.

As for taxis, he said the toll could be set at HK$25, the same as that for the three cross-harbour tunnels.

"Compared with the current situation, perhaps some truck drivers using Tuen Mun Road may turn to Tai Lam Tunnel (during peak hours in future), causing further congestion," he told RTHK.

"So I believe if the government charges the time-varying tolls, that can allow the spread of traffic in an orderly manner. I think that's a good thing."

The tunnel's 30-year franchise began in 1995 and is currently fully-owned by a subsidiary of Sun Hung Kai Properties.