Government advisers have strengthened calls for China to further ease its stringent one-child policy urgently, ahead of a meeting this month during which the Communist Party's decision-making body will set the tone for national economic and social development for the next five years. In a report recently submitted to the authorities, China's top think tanks urged Beijing to immediately relax restrictions on the number of children couples are allowed to have, according to an academic with knowledge of the matter. The report was based on a survey jointly conducted by several institutes including the Chinese Academy of Social Sciences, Renmin University and a think tank under the national family planning office, said the academic, who did not want to be named. "There is already a consensus among China's demographers that the limits should be relaxed," said Wang Feng, a demographer with the University of California, Irvine, and a guest professor at Fudan University. "It's … already too late to be doing so." While the survey's contents were not made public, an earlier report by the China Business Network, a consultancy group, said it included predictions of the population trend and when it would peak. The survey had been commissioned by the decision-making authorities, highlighting the likelihood of a revision in the policy, the group said. In a separate proposal earlier this year, Wang and 38 demographers from 21 institutions called for the one-child policy to be eased as soon as possible. It noted that a 2013 relaxation of the policy had had limited impact and that further measures were necessary to counter China's low birth rate, greying population and dwindling workforce. The policy - which previously allowed only parents who were both the only child to have a second baby - was relaxed in 2013 so couples where only one parent was a single child also became eligible to have two children. The authorities expected 20million new births in 2014, but only 16.9 million babies were born. By May this year, only 1.45 million couples - out of 11 million eligible ones - had applied to have a second child. The figures reflected a surprisingly low level of interest. Further loosening the family planning policy would help beef up China's labour supply and ease the pressure on the greying population, according to the proposal. It would also help drive up domestic consumption, which would in turn support steady economic growth. READ MORE: How one-child policy plucked a girl from China to US and gave her undreamt-of opportunities The mainland's birth rate is 1.18 children for every couple - significantly lower than the global average of 2.5 and the 1.7 average in developed countries. "China has undergone a birth rate below the replacement level of 2.1 for 20 years straight. Its population will no doubt start to decrease in 10 years, even if the one-child policy is further relaxed immediately," Wang said. Wang said even several scholars who had long supported maintaining the status quo had recently called for the restrictions to be relaxed. Renmin University's top demographer Zhai Zhenwu, an adviser on the one-child policy, in March said it was now appropriate to loosen the policy. "Balanced development means having the population stay at the same level," said Renmin University demographer Zhou Xiaozheng, referring to Beijing's statement in 2012 that the country needed "balanced demographic development". "We should not forget that there is an increasing number of couples who are not interested in having children," Zhou said. Still, there remains those who argue against further easing the one-child policy. "An insufficient workforce is more an employment issue than a lack of population," said Hou Dongmin, also a demographer at Renmin University.