The transport minister threatened to prosecute taxi and goods-van drivers if there was a repeat of the slow-drive protests at the weekend which halted passenger traffic to and from the airport by road for up to seven hours. Police said the 200-plus taxi drivers who took part in a slow drive on Saturday may have broken the law and could be prosecuted. The warnings came after accusations that the government had yielded to pressure from radio-taxi operators by allowing them to park nearer the airport's terminal buildings a day after the blockades. Kwok Chi-pui, a representative of radio-taxi groups, said they were told on Wednesday that pickup points at the airport's No1 and No4 car parks, within a few minutes' walking distance of the terminal buildings, would have to move to a car park 30 minutes' walk away. This followed complaints from metered-taxi drivers that radio-taxi drivers had been illegally snatching business by undercutting metered fares by at least 20 per cent. Wednesday's notice, issued by the Airport Authority and the Transport Department, also affected goods-van drivers locked in a long-running dispute with the taxi trade over the illegal carriage of passengers without luggage. The notice was rescinded after the two groups staged slow-drive protests over the weekend. As an interim measure, radio-taxi drivers have been allowed to pick up passengers from an area at the back of the No4 car park. The concession will be reviewed after seven days. Four taxi associations expressed dismay at the decision in a meeting with the Transport Department. 'The law-abiding drivers join long queues outside the airport to wait for passengers - sometimes it takes more than five hours - but these discount-taxi groups just roll in and snatch our business. Is this fair to those who spend a whole day waiting?' said To Sun-tong, of the Motor Transport Workers General Union. Goods van drivers are also dissatisfied that only radio taxis have been allowed to pick up passengers at the No4 car park. Secretary for Transport and Housing Eva Cheng Yu-wah said allowing radio taxis into the airport was meant to offer passengers more choice, but that had to be balanced with maintaining law and order. 'The government will enforce the law in a serious manner. I believe we all agree maintaining smooth traffic in the airport area is of tremendous importance. 'To express one's opinion through a road blockade is unacceptable,' she said. Police said they had not arrested any protesters on Saturday, but a spokeswoman said anyone who disrupted traffic on purpose was in breach of the Traffic Ordinance, and protesters who failed to seek prior approval for gatherings involving more than 30 participants were in breach of the Public Order Ordinance.