China should consider adjusting its family planning policy, as structural problems have overtaken excessive growth as the most significant population-related problem, a government think tank said Friday.

Problems in population structure, quality and distribution have become increasingly visible and will have a profound impact on China's future social and economic development, the China Development Research Foundation (CDRF) said in a report.

China's population has seen a declining annual growth rate, slowing to 0.57 percent in the first decade of the 21st century, down from 1.07 percent in the previous ten years, according to the report.

China's population situation is quite different from that of 30 years ago, when a family planning policy that limited the majority of urban families to one child took effect, the report said.

The report said the population is heading for negative growth and an ultra-low fertility rate, as well as faces issues related to aging, gender imbalances, urbanization, an expanding shortage of migrant workers and an only-child generation.

The CDRF said the government should gradually loosen the one-child policy over the next three years in regions where family planning has been strictly implemented.

By 2020, there will be no need to continue birth planning, as people will make more rational decisions on birth issues, said the CDRF.

The CDRF said China will have an ultra-low fertility rate after 2026 and that the government should start encouraging families to have more children.

The family planning policy was introduced around 1980 to rein in China's surging population by encouraging late marriages and pregnancies, as well as limiting most urban couples to one child and most rural couples to two children.

"The family planning policy has had a profound influence on China's economic and social development," said the CDRF.

The implementation of the policy has reduced the pressure created by a rapidly rising population, made contributions to economic growth and helped improve population quality, it said.

However, China has paid a huge political and social cost for the policy, as it has resulted in social conflict, high administrative costs and led indirectly to a long-term gender imbalance at birth, the report said.

Efforts should be made to support one-child and disadvantaged families in family planning, the CDRF said.