Hong Kong-listed developers will struggle to maintain 30 per cent growth in property sales over the next few years due to constraints on building land banks on the mainland, according to analysts at investment bank BNP Paribas. "Currently, expanding land bank is particularly difficult in tier-one and tier-two cities owing to accelerating land price growth, which is significantly outpacing property price growth in these cities due to the 'herd mentality' of developers in making acquisitions," wrote Lee Wee Liat, the head of property research at BNP Paribas Securities (Asia), in a report just released. Land prices in the first-tier cities - Shanghai, Beijing, Shenzhen and Guangzhou - had increased by 135 per cent year on year by the end of September, compared to an average 15 per cent increase in selling prices in those cities, the report noted. In second-tier cities land prices were up 43 per cent versus a 4 per cent rise in average selling prices during the same period, while land prices in third-tier cities were up 11 per cent versus a 1 per cent rise in home prices. The surge in land prices has arisen as developers bid fiercely in government land auctions. Last week Evergrande Real Estate paid 9.68 billion yuan (HK$12.35 billion) for six residential sites in Shanghai and Nanjing. The six sites were sold separately at a premium of between 79 per cent and 149 per cent above opening bids. Evergrande said in the first 11 months of the year it generated contract sales of 98.38 billion yuan, up 16.3 per cent for the whole of last year. Citing Evergrande, the largest developer in Guangzhou, as an example, the report calculated that it would need a land bank of 192.2 million square metres - up 37 per cent from its present 140 million sq metres - if it wished to achieve 30 per cent growth in property sales next year. Few developers could achieve such a fast pace of land acquisitions, said Lee of BNP Paribas. Contracted sales growth exceeded construction rates for most developers in the past 12 months, said Lee. As a result developers would need to significantly increase sell-through rates to achieve similar contracted sales growth next year, he said.