A video clip of a girl being abused by her mother during a photo shoot went viral this week, raising concerns about child labor in the child modeling industry.

The 10-second clip that began appearing on Sina Weibo on Monday shows the girl, identified as Niuniu - who is about age 5 - being kicked by a woman at a photo studio in Hangzhou, Zhejiang province, after she put down a flower basket prop.

The woman was heard warning the girl to be attentive and not make her angry. The girl staggered, though she didn't fall.

The unnamed woman was said to be Niuniu's mother, and the pair were shooting pictures for a children's clothing business on Taobao, the online marketplace.

The clip soon went viral, with many accusing the mother of child abuse and exploiting the girl for money.

On Tuesday, a Sina Weibo user who claimed to be the owner of the Taobao shop, said she was upset about the way Niuniu had been treated and had decided to stop working with the mother.

Another user, who identified herself as the woman in the video, apologized on Wednesday, saying she loved her daughter and that she meant no harm. China Youth Daily said later that it had confirmed the apology was from the mother.

Even so, more clips were released showing the mother's actions, including one in which the girl was whipped once with a hanger.

Experts said that China's child modeling industry has been expanding rapidly in recent years because of the explosion of online marketplaces and is fueled by parents who want their youngsters to pick up a talent and manage stage fright, which could benefit their career when they grow up.

But others believe it's the lucrative financial rewards that really lie behind the trend.

Zhang Ai, who owns the Beijing-based child modeling agency Halleystar, said the hourly pay for a child is around 500 yuan ($74) and may exceed their adult counterparts. The pay varies depending on their looks and the way they perform in front of the cameras.

"They can earn up to 4,000 yuan in a single day," Zhang said.

But the money has sparked concerns that children may be forced to pose by money-driven parents.

Yang Baoquan, a lawyer who focuses on labor relations at Zhong Yin Law Firm in Beijing, said China's current rules on child labor only forbid hiring workers under age 16 as full-time employees, but there have been no deliberations about cases such as Niuniu's.

"It's kind of like a business cooperation with parental consent," he said.

Zhang Jing, head of the Family Development Research Center at China Women's University, said the case highlighted the urgency for legislators to draw lines between the things that parents can and cannot do.

"Laws should provide more detail to fill the legal vacuum in child labor," she said.