Experts have renewed calls for a government department to oversee child protection cases after a couple in Hunan province was accused of beating their adopted daughter to death.

Police in Hunan said a couple was detained last month on suspicion of killing the 3-year-old girl.

Police did not identify the husband's name because an investigation into the death is ongoing. However, the woman has been identified in Chinese media as having the surname Yi.

The family's lawyer, Huang Fulin, said on Thursday that Yi severely beat her daughter for wetting her pants on Nov 24 at their home in Zhuzhou's Lusong district.

The next day, when the parents came home from work, they found the child dead. The father then notified police of the beating.

Huang said Yi has confessed that she repeatedly beat her adopted daughter to correct bad habits.

Local media reported that neighbors had warned police in September that the couple had beaten the girl, but officers agreed to let the child remain with the family instead of sending her to a foster home.

The tragedy has prompted calls for more public awareness and professional services to prevent child abuse. Currently, child abuse cases and child protection services fall under the jurisdiction of various government departments. Cong Zhongxiao, director of the China National Children's Center, said the government urgently needs to establish a central department to oversee efforts.

"Children are often too young to file a complaint of domestic violence, so a quick response system is essential," she said.

The abuse of children is a longstanding problem in China, where many people still think domestic violence is a "private affair", Cong said.

She called for communities to have designated child protection stations to provide shelter for victims of domestic violence.

Tong Xiaojun, a professor for the Political Sciences' China Social Work Research Center at China Youth University, said deaths can be avoided if parents have access to professional services.

An assessment and support system is also needed for parents who adopt children. Follow-up sessions and training are also necessary for adoptive parents, she said.

If authorities had acted sooner, Yi's child might still be alive, she said.

"Society lacks basic knowledge of child protection, and many parents actually see their abuse as good for the child," Tong said.

Feng Zhiwei in Changsha contributed to this story.