A two-year delay in the completion of the HK$67 billion high-speed railway connecting Hong Kong with Shenzhen and Guangzhou will have a serious impact on the Pearl River Delta, government advisers say. Shenzhen officials - always cautious when commenting on Hong Kong - complained they had yet to be formally notified by the Hong Kong side. "We are very sorry … so far we haven't been told by any Hong Kong department [about the delay]. What we can do is to make sure that our section will be completed on schedule," said an official from Shenzhen involved in the project, who refused to be identified. Mainland government advisers were much more blunt. Zheng Tianxiang, a provincial policy adviser involved in several infrastructure projects - said the delay would "definitely affect" the pace of the Pearl River Delta's integration. A plan to streamline travel time to no more than an hour between each of the economically powerful delta region's cities is at the centre of the Guangdong government's development blueprint. Local authorities believe this will create capital and prompt a flow of talent to help the region upgrade its economy. "For this to happen, all sections of the key infrastructure projects must be completed and connected synchronously. If one part gets delayed, the whole plan will be affected," Zheng said. Zheng said the delay would affect the profitability of the rest of the rail link. The section between Guangzhou and Shenzhen is already open but ridership is low because most potential customers want to come to Hong Kong instead of Shenzhen. "The passenger flow is much lower than we expected because the Hong Kong side is lagging behind. Now we are told there will be another two-years of delay," Zheng said. "Would the Hong Kong government take up the responsibilities for the poor return of the Guangzhou-Shenzhen express railway?" Ding Li, a planning expert at the Guangdong Academy of Social Sciences, blamed the "weak determination and political will" of the Hong Kong government in pushing for cross-border co-operation. "The delays will make our regional integration progress look bad in the eyes of Beijing. Integration is the only future for the delta. If one falls behind, all fall behind." The MTR Corporation disclosed the delay on Tuesday, citing the breakdown of a tunnelling machine at Yuen Long as the main problem. It means construction, which started in 2010, will not be finished until 2016, with services starting in 2017. When announced, the project was to be finished next year. MTR officials have said additional costs due to the delay would be covered by a HK$4.4 billion contingency fund.