TEHRAN - The population of China, the world’s most populous country, will peak in 2029 at 1.44 billion before beginning a period of “unstoppable” decline, a government report has said.

China Academy of Social Sciences (CASS) report states that the country must implement policies to handle a smaller workforce and an older population.

Both changes combined could cause "very unfavorable social and economic consequences", the report says.

Working population numbers were now stagnating, the report said, with a low fertility rate set to cause further issues. If fertility rates stay low, the population could drop as low as 1.17 billion by 2065.

By the middle of the century, China's population is expected to drop to 1.36 billion – a fall in the labour force of close to 200 million.

The study also predicted a rise in the dependency rate, meaning the proportion of non-working people like the elderly and children.

In 2015, the world's most populous country ended its one-child policy in a bid to tackle the problems. While relaxing the one-child policy will help long-term, in the short term it will create more dependents, according to the report.

Previous forecasts reportedly suggest China's elderly population could hit 400 million by 2035, up from 240 million in 2017.

China has been the most populous country for many centuries. When China had its first post-1949 census in 1953, the population stood at 583 million. By the fifth census in 2000, the population had more than doubled, reaching 1.2 billion.