The bridge linking Hong Kong with Macau and Zhuhai might be delayed until 2017 or even later, a top Guangdong official has said. The project, with an estimated total cost of HK$133 billion, has been hit by numerous technical challenges, and Li Chunhong, the director general of Guangdong's Development and Reform Commission, warns more problems could arise. "I can just say it's very, very difficult to have the bridge put into use by 2016," Li said at a press conference at the provincial People's Congress in Guangzhou yesterday. It was difficult to promise an opening even the following year. "It's hard to offer a fixed schedule … We don't know if there will be more problems ahead," Li said. The 50km-long link consists of three cable-stayed bridges, two artificial islands, and a 6.7km-long immersed tube tunnel, situated off Lantau. Li said sinking and docking the tube tunnel was the most complicated part of the project. The section consists of 33 tubes and the first one was successfully docked in May, 2013, Li said. "As of now, only 14 tubes have been docked and completed." He said attempts since October to dock the 15th tube had failed because the volume of sand sediment on the seafloor was different. "We have analysed it for three months with all kinds of simulations by supercomputers, but finally, we're still unsure of the exact reason. It's too difficult," Li said. The costs of the bridge will be split between Hong Kong, Macau and mainland authorities. Hong Kong's contribution, including a new island, will come to about HK$87 billion. The link will cut travel time to Zhuhai from more than three hours to 30 minutes. Zheng Tianxiang, a Pearl River Delta transport expert, said the project was started without adequate appreciation of the scale of the difficulties involved. "They did not spend enough money and time on understanding the basic engineering geological conditions in the sea," Zheng said. Li also spoke about the development of the Guangdong Free Trade Zone, which is expected to play a major role in deepening cooperation with Hong Kong and Macau. The 116 sq km zone stretches across parts of Guangzhou's Nansha New Area, Qianhai and Shekou in Shenzhen, and Hengqin in Zhuhai . "Our preliminary studies suggest that Qianhai's main function is to maintain Hong Kong's long-term stability and prosperity while Hengqin would support Macau to diversify it's economic structure," Li said on the sidelines of the congress. "We are still studying how to classify the function of each of the three areas enlisted for the Guangdong Free Trade Zone," Li said. Li told reporters the Guangdong government had been actively drafting the implementation measures of the zone, which should be ready soon. "According to our understanding, more than 30 departments have reached consensus over the implementation measures … I expect this should be ready soon," Li said. Although he refused to say when the zone would open, Li had previously told local media it would be after Lunar New Year. The timing was confirmed by Li Jia , the party secretary of Zhuhai, who spoke on the sidelines of the congress on Monday.