Twenty-nine of 31 provincial-level regions in the Chinese mainland have relaxed the one-child policy, with some 90 million couples expressing their willingness to have a second baby, said the National Health and Family Planning Commission (NHFPC) on Thursday.

The new policy, allowing couples to have two children if either parent is an only child, was first officially implemented in Zhejiang Province on January 17 this year. Henan Province was the last to follow suit at the end of May.

The Tibet Autonomous Region and the Xinjiang Uyghur Autonomous Region have not yet made any changes to existing policy, said Yang Wenzhuang, an official with the NHFPC, at a press conference. 

As of May 31, a total of 271,600 couples have submitted their application to give birth to a second child, among whom 88.8 percent have been approved, according to Yang.

These figures are only one seventh of the predicted number of 2 million per year.

"Judging from the number of applicants, the new policy will not bring an expansion of Chinese population, and will not affect [China's] social and economic development during the next few years," said Huang Wenzheng, a columnist and former research fellow with Harvard University.

The NHFPC conducted research on people's willingness to give birth to a second child in 29 provincial regions last year. The results showed that 80 percent of families want to have two children, while 60 percent of those who already have one child expressed a willingness to have a second child.

"We [should] encourage more couples to give birth to children, as it will help to contravene the aging of [China's] population," He Yafu, an expert on population and family planning, told the Global Times on Thursday.

The new policy is off to a good start, but it will not bring a baby boom, said Yang, the official with the NHFPC.

"My wife wants to have a second baby, but I think this plan will not work for at least three or four years due to our financial situation," Zhang Wei, an army officer, told the Global Times.

"Many of the people I know who decide to have a second child are wealthy enough to afford a second child, although their wives might be too old to have children," added Zhang.