A review of tunnel roadworks was promised yesterday after thousands of commuters were caught in snarl-ups when part of the Cross-Harbour Tunnel was closed during the morning rush hour. There were long queues of traffic on all major approaches to the tunnel on Hong Kong Island, stretching as far as Taikoo Shing in the east and Sai Ying Pun in the west. New World First Bus said about 50 of its Hong Kong Island and cross-harbour routes - nearly half its fleet - were affected. First Bus said it had to shorten some routes and put 14 extra buses into service. Its inspectors were also sent to congested areas to monitor the situation and to some stops to advise disgruntled passengers. The operator received 50 complaints during the morning. Citybus said the chaos had disrupted 30 routes, while Kowloon Motor Bus said 25 routes were affected. The Highways Department said the trouble began just after 5am when a pipe to one of its pavers - a machine used to lay the road surface - burst and spilled engine oil on to a newly asphalted road inside the Kowloon-bound section of the tunnel. Its complaints unit officer, Luk Wai-hung, said the accident meant the road had to be dug up again and the work could not finish at 6.30am as planned. 'Since the engine oil fell on the existing asphalt road, we had to re-lay the surface before we could open the road for public use,' he said. 'If we had reopened the road as it was it would have been very unsafe.' He admitted the delay was made worse by a lack of spare asphalt on site. The lane was finally reopened at about 9.45am, but traffic did not get back to normal until midday. The work was part of a three-month road resurfacing programme in the tunnel that will finish in January. The Transport Department said it had received conflicting information on the work's progress and therefore could not inform motorists and bus companies accurately. Deputy Commissioner for Transport Dorothy Chan Yuen Tak-fai said the tunnel operator would submit a report. 'In our review, we will also study proposals that require tunnel operators to limit road surface works to non-peak hours only,' she said. Democratic Alliance for the Betterment of Hong Kong legislator Lau Kong-wah said although it was an accident, the authorities had been too slow to inform the public and commuters did not have time to alter travel plans. 'The Transport Department should establish guidelines regarding roadworks in major tunnels such as the Cross-Harbour Tunnel and the Lion Rock Tunnel,' he said. An average of more than 120,000 vehicles used the tunnel each day last year.