Chinese Premier Li Keqiang on Sunday said China is still reviewing adjustments to the country's birth policy implemented in 2014 in order to decide whether further changes are needed.

Speaking at a press conference after conclusion of the annual parliamentary session, Li said authorities are currently conducting comprehensive reviews on the implementation of the birth policy which now allows couples to have two children if either parent is an only child.

"[We will] make improvements and adjustments to the policy in accordance with legal procedures," the premier said, without giving a specific time frame.

China, the world's most populous country, first introduced its family planning policy in the late 1970s to rein in surging population by limiting most urban couples to one child and most rural couples to two if the first child was a girl.

A major policy change was adopted at the end of 2013, stipulating that couples nationwide may now have a second child if either parent is an only child.

The adjustment. which was put into practice in early 2014, did not lead to a baby boom many had expected, and experts are now suggesting a full implementation of the two-child policy.

However, Li said authorities are still "weighing pros and cons ... based on the outcome of the comprehensive review and taking into accounts China's economic and social development as well as changes in the demographic structure."

Statistics from the China Population Association showed that China had registered some 16.9 million new births in 2014, 470,000 more than the previous year.

The figure is expected to be raised by another one million this year thanks to the easing birth policy, the association said in Feburary

Chinese authorities had in the past defended the country's previous one-child policy, saying it had prevented around 400 million people from being added to China's population.

But one-child policy did lead to a number of social problems over the years.

Earlier reports said China's labor force had decreased by 3.45 million year on year in 2012, marking the first "absolute decrease" since China's reform and opening up in 1979.

As of 2013, the number of Chinese people aged 60 or above exceeded 202 million, 8.53 million more than in 2012 and already accounting for 15 percent of the total population, up 0.6 percentage points.

Gender imbalance is another side effect of the one-child policy, as a result of Chinese parents' preference for boys.

In 2014, the sex ratio of newborns stood at 115.88 to 100 (men to women).