Cross-border permits might be redesigned, Chinese officials said yesterday, as the extent of the operation by forgery syndicates emerged. Guangdong police yesterday began investigating a fresh case of suspected forged permits days after they smashed a Hong Kong-Guangzhou syndicate. Six key syndicate members, including at least one Hong Kong man, have been detained pending charges of forgery. The case has been handed to the procuratorate for investigation. Hong Kong triads are believed to be involved with links extending as far as Beijing. Hundreds of high-quality forged one-way permits are believed to be circulating. It was not until officers spotted discrepancies between data on a permit and the holders' records that the case was brought to light, a Guangdong public security bureau source said. The source disclosed they were targeting another active syndicate. 'We know there is at least one other active syndicate forging the document. We are investigating it.' A bureau spokesman also says it may consider a new permit design to make it harder for swindlers to forge. 'We may look into the possibility of issuing a new design. We want to stress that obtaining a permit outside official channels is illegal and people should report swindlers.' Some people were said to have paid up to one million yuan (about HK$934,700) to buy a permit. Under Chinese regulations, the fee for applying for a one-way permit is five yuan and the permit costs 50 yuan. Meanwhile, Shenzhen has stepped up its frontier defence to stop illegal immigrations. The first batch of 11 patrol boats and vessels have arrived moored at Cape Beizai, near Yantian port.