Surveyors have urged the government to spend $1.9 billion over 10 years to conduct a systematic boundary survey of about 210,000 plots in the New Territories in a move to prevent land disputes. The proposal, made by the Hong Kong Institute of Surveyors, came after the South China Morning Post reported on Monday that thousands of village houses may have been built illegally on government land in the New Territories. Officials discovered the extent of the problem during a clearance operation last month when it emerged that about a third of the 200 houses at Lam Hau Tsuen in Yuen Long occupied government land. Legislator Lau Ping-cheung, representing the architectural, surveying and planning sector, said methods used to conduct the last survey of the New Territories about 100 years ago did not meet today's standards. The problem in Lam Hau Tsuen might have resulted from unclear land boundaries in villages, he said. The institute said a precise land record, created by using advanced survey techniques such as global-positioning technology, could reduce land disputes and make land transactions smoother. 'It is vital for efficient land management and timely completion of infrastructure development,' Mr Lau said. The institute proposed that the government conduct a precise numerical boundary survey of the estimated 210,000 lots in the New Territories to replace the existing graphical record. It said it would cost about $1.9 billion and take 10 years to complete.