A national survey will be conducted of left-behind children in rural areas, authorities said on Tuesday.
The survey, which will run until late July, will be conducted by the ministries of civil affairs, education and public security.
Information on the children, including how many there are, as well as their family and education, is expected to be released at the end of August.
"There are no accurate national statistics of left-behind children in rural areas. The upcoming survey is designed to understand their real situation and better support those children in need," said Wang Jinhua, head of the Social Affairs Department of the Ministry of Civil Affairs.
The survey will focus on children under 16 whose parents are both migrant workers and absent from home, or where one parent is a migrant worker and the other is unable to provide care.
Children's personal and family information will be registered.
Personal information includes date of birth, sex, education, identification number, residential address, health and whether they board at school. Family information includes parents' working address, the major source of family income and guardian information.
According to a survey released by the All-China Women's Federation in 2013, China has about 61 million left-behind children.
The Ministry of Education said that in 2015 there were more than 20 million left-behind children in rural areas from grades 1 to 9.
"The upcoming survey expands the age, collecting information from 0 to 16, not only limited to the school age kids," said Du Kewei, an official from the Ministry of Education.
In recent years, a number of tragedies have called attention to the plight of those children.
Last year in Bijie, Guizhou province, four children of absent migrant workers committed suicide at home. They were aged 5 to 13.
Also in Bijie last year, a 15-year-old girl and her 13-year-old brother were killed at home. Police found that the girl had been sexually assaulted before she was murdered. Their parents were migrant workers away from home.
"The best way to solve the plight of left-behind children is to allow them to grow up with their parents. The survey might be able to allow government to make further policies toward that goal," said Yang Yuansong, a teacher from a rural area in Guizhou.