Most couples applying to have a second child will deliver their babies this year, rebuffing speculation that the measure is unpopular.

With an aging society and potential shortage of workers, most provinces have relaxed family planning rules to allow couples a second child if one parent is an only child.

"The measure was launched in 2014, and will show its effects this year," Zhai Zhenwu, director of the Sociology and Population School under Renmin University of China, was quoted as saying by People's Daily on Friday.

It's estimated that 60 percent of the 11 million couples eligible will have another child over the next four to five years, with one to two million being born each year.

In terms of couples wishing to have a second child, conditions varied in each area as the measure is proving more popular in western China and small cities than coastal regions and large cities.

"In some provinces, the number of couples choosing to have a second child is higher than expected while in other areas it is lower," Zhai said. "So it is not correct to say that the policy is unpopular".

Yang Wenzhuang, director of the family planning grassroots guidance department under the National Health and Family Planning Commission, said that by the end of last year about 1.07 million couples had applied to have a second child, a number that meets expectations.

Changes to family planning policy came at a time when an aging society, imbalanced gender ratio and decline in the working age population began to notice. Under the policy, in place for more than 30 years, most families were restricted to one child.

According to the National Statistics Bureau China, as of last year, had 915.83 million people aged between 16 and 59, a range viewed as suitable for working. But that was a decline of 3.71 million on the previous year and the third in a row.

China may become a "super aging society" by 2035, when every two workers will need to support one elderly resident, demographers said.