China, the world's largest exporter, might face a trade deficit in the next five to 10 years as the second-biggest economy is ramping up imports, a former top Chinese official has said. China could no longer rely on exports to expand its economy as it had done over the past 30 years, said Zhang Yansheng, former secretary general of an academic committee at the National Development and Reform Commission. This is because exports became unsustainable and would put too much strain on ties with the rest of the world, specially as protectionism grew, he said. "The next stage is an open economy that focuses on a balance of trade," Zhang told Hong Kong-based South China Morning Post. "Expanding imports is a very significant part of China becoming a big global power," he said. China's export and import volumes rose 14.2 per cent year on year to 27.79 trillion yuan (USD 4.28 trillion) last year, ending the continuous drop in the previous two years, according to the official data quoted by state-run Xinhua news agency. China's exports increased 10.8 per cent to reach 15.33 trillion yuan while imports surged 18.7 per cent to 12.46 trillion yuan in 2017, the General Administration of Customs (GAC) said. The trade surplus continued to narrow last year, shrinking 14.2 per cent to 2.87 trillion yuan, compared to a reduction of 9.1 per cent registered in 2016 that saw 3.35 trillion yuan in trade surplus.