Keeping the Lowu border checkpoint open 24 hours a day may damage Hong Kong's economy and lead to more men having mainland mistresses, according to a recent survey by the Democratic Party. Democrat Wong Sing-chi, a Northern District councillor, said the Government should assess the impact of having the checkpoint open round the clock. There has been pressure to make the Lowu checkpoint a 24-hour operation, but currently officials are only extending the closing time by half an hour on public holidays. Some 507 residents of Sha Tin, Tai Po and the northern New Territories were interviewed for last week's survey. About 300 of them thought that permanently opening the checkpoint would adversely affect Hong Kong. Of these, 188 believed the retail sector would be affected. Many are worried that Hong Kong residents would flock to shops in Shenzhen, noise pollution from railways would increase or that the property market would be hit. Hong Kong men would have more opportunity to find mistresses on the mainland, they said. Only 38 per cent believed a round-the-clock operation would have a positive effect on Hong Kong as it would help clear crowds at the checkpoint.