Close watch: Permanent Secretary for Environment, Transport & Works Joshua Law (centre) visits the Emergency Transport Co-ordination Centre with Commissioner for Transport Robert Footman.

Although traffic flow on both sides of the harbour remained normal on the first day after the Eastern Harbour Crossing revised its toll, the Government will keep the conditions under watch.

Permanent Secretary for Environment, Transport & Works Joshua Law said the Government will review its contingency arrangements and make adjustments when needed.

Mr Law visited the Transport Department's Emergency Traffic Co-ordination Centre today, which was activated at 7am to monitor cross-harbour traffic after the Eastern Harbour Crossing increased its tolls.

From midnight to 8pm vehicles using the Cross Harbour Tunnel rose 5%, about 4,700 vehicles, and the Western Harbour Tunnel rose 18%, about 3,800 vehicles, compared to a normal Sunday. Vehicles using the eastern tunnel fell by 39%, about 21,300.

Mr Law said there will be close communication between centre staff, Police, franchised bus companies and tunnel management companies. He called on commuters to plan their trips early on Tuesday, the first working day after the toll increase.

"Those who need to cross the harbour for work, study or public examinations should start their journey early. If possible, please avoid driving through the cross-habour tunnels during rush hours and consider using public transport such as the mass transit railways or ferries," he said.