Construction bosses yesterday proposed more flexible work hours as one possible solution to the problem of workers being struck down by heatstroke. 'We can consider setting working hours from 7am to 8pm instead of 7am to 7pm, giving two hours for workers to rest, or let workers leave at 5.30pm instead of 6pm,' Gammon Construction chief executive Thomas Ho On-sing said. Mr Ho was speaking at a Construction Industry Council meeting following the Labour Department's release on Wednesday of official guidelines to tackle searing temperatures. Council member Conrad Wong Tin-cheung, president of the Hong Kong Construction Association, said the group had written to various trade organisations and labour unions about extending hours so that workers could enjoy an extra hour for lunch and rest. But reactions were mixed, he said. 'Some are supportive and some are not, as some are concerned that they might go home late,' Mr Wong said. 'Some argue different trades have different practices, and some work inside buildings on sites, so risk exposure is not quite the same.' He said extending working hours would require a change in legislation because noise control regulations were effective from 7am to 7pm. 'We have already talked to the director of the Environmental Protection Department,' Mr Wong said. 'He sounded supportive, but there are many hurdles to overcome.' Choi Chun-wa, chairman of the Hong Kong Construction Industry Workers' General Union, welcomed the Labour Department guidelines but reiterated that they should be made compulsory. 'The government should make sure these guidelines will be implemented on-site,' he said. 'It should make it compulsory for private developers, contractors and frontline workers to follow the guidelines. 'Apart from the guidelines, employers should also provide plenty of water and shelter for workers on-site so they can rest in shaded areas if they feel unwell during outdoor work.' The guidelines, issued after a series of heatstroke cases, including the death of a worker reportedly due to heat exposure at a golf course construction site, urge building sites to prevent heatstroke by helping workers avoid working in direct sunlight and improving ventilation or air-conditioning systems at workplaces.