Migrant workers from Southwest China who leave their children at home perform worse at parenting then compared with their peers in East China, a survey found.

"The frequency of migrant parents seeing and contacting their children in different regions varies," said Li Yifei, senior researcher at the Scientific Communication and Education Research Center at Beijing Normal University, who led the survey.

The survey was conducted by On the Way to School, an NGO.

It found that migrant parents in eastern regions and provinces visit and contact their children more frequently than those in other places.

"The frequency of parents visiting or contacting their children is of the greatest importance for children's psychological health," said Liu Xinyu, founder of On the Way to School.

"Parents who are migrant workers should care more about their left-behind children by contacting or visiting them more frequently," Liu said.

From October to April, almost 7,000 responses were collected in 14 provinces.

"Through the survey, we realized that the worst situation for left-behind children is when both parents are working away from home," Liu said. "In these cases, parents make telephone calls or come back home to visit their children the least frequently."

A similar survey released by On the Way to School last year showed that about 15 percent of left-behind children had no physical contact with their parents in a year. Four percent received telephone calls from parents once a year.

Zhai Meixiang, 12, sees her parents once a year during Spring Festival.

"When I miss them, I make telephone calls to them. But in most cases, I solve problems on my own," she said.

Zhai lives in Central China's Hunan province. Her parents headed to work in East China's Zhejiang province and left her behind when she was 4.

"I was not happy at first and complained a lot. But I can understand them now," the girl said, adding that her parents are saving money for her future.

According to the All China Women's Federation, China had about 61 million left-behind children in 2013.

Although China has experienced rapid industrialization and urbanization since the 1980s, the pace of change has accelerated in the last 20 years. That has led to millions of rural residents flocking to large cities in search of work, leaving their underage children in the care of grandparents, relatives, or even to fend for themselves.

More tragically, a number of incidents have attracted attention to their plight. Last year in Bijie, Southwest China's Guizhou province, four left-behind children, aged 5 to 13, committed suicide at home.