A 67-year-old woman has given birth in China, a hospital said Monday, with the parents claiming they are the country's oldest couple to conceive a baby naturally.

The woman, surnamed Tian, delivered a healthy girl by Caesarean section on Friday, Zaozhuang city's Maternity and Child Health Care Hospital told AFP.

"The child was bestowed on the two of us by heaven," Tian's 68-year-old husband, surnamed Huang, told Chinese news site guancha.cn.

Tian told Jinan Times that she only discovered that she was pregnant when she went to the hospital for a health check, telling the newspaper: "I didn't want it, initially."

The hospital said it could not confirm that Tian had conceived naturally as she was already pregnant when it took her as a patient.

The Global Times reported the new baby girl was called "Tianci", meaning "gift from heaven".

The Jinan Times said Tian already had two children, including a son born in 1977, two years before China imposed a one-child policy to control its burgeoning population.

Reports of the birth drew criticism on China's Twitter-like Weibo platform.

"The parents are too selfish," one commenter wrote. "At their advanced age they have no ability to take care of a kid, and the pressure will be on the older siblings."

"Poor child, he's going to start taking care of his elderly parents by the time he's 20," wrote another.

Others wondered if Tian and Huang would be penalized for having more than the current allowance of two children.

In 2016, Beijing relaxed the one-child policy, allowing families to have two.

While Tian's age makes her an outlier, women in China are increasingly delaying childbirth or choosing not to have children after decades of strict family planning policies that have made small families the norm.

The age at which the average Chinese woman has her first child rose from 24.3 years in 2006 to 26.9 years in 2016, according to a report this year by the Economist Intelligence Unit.

While the two-child policy has had a smaller effect on China's birth count than expected, it has prompted more older women to consider having second children.

Around 51 percent of newborns in 2017 were second children, compared to around 40 percent in 2016, the Economist Intelligence Unit report said.

Other women in their 60s and 70s have given birth in recent years, though generally after having fertility treatment.

The China Daily reported in December 2016 that a 64-year-old woman gave birth to a baby boy by Caesarean section after IVF treatment in the country's northeast Jilin province.

And in 2016, a woman in India gave birth to her first child in her 70s, following two years of IVF treatment.

A 65-year-old German woman was reported to have given birth to quadruplets in 2015, after undergoing an artificial insemination procedure in Ukraine.