Cross-border surveillance for infectious diseases was lax at the Hong Kong-Shenzhen border yesterday, despite a pledge by health officials to stay on high alert after a suspected Sars case in Guangzhou. With the case still under investigation, a South China Morning Post reporter was able to cross the Shenzhen and Lowu checkpoints without completing a health declaration form. Infrared censors have been installed at the checkpoints to measure travellers' temperatures and publicity leaflets about prevention of the disease are also on display. Travellers are required to fill out health declaration forms, on which they must declare if they have had contact with a Sars patient over the past 10 days and whether they have a cough or fever. But the Post reporter passed through the Shenzhen border with an incomplete form and, like other travellers, was only asked to leave the form in front of the immigration counter. On the Hong Kong side, immigration officers appeared more rigorous in checking the forms. But again, with an incomplete declaration form, the reporter passed the checkpoint without being asked one question. Director of Health Lam Ping-yan visited the Shenzhen border this week to discuss improved border controls with mainland officials. He said Shenzhen officials promised to step up health checks at the border.