The poll of 2000 adults by the Royal Children's Hospital also found parents were six times more likely to be concerned about obesity in children other than their own.

The survey asked people to rate 29 childhood health issues, including allergies, cancer and asthma.

Dr Anthea Rhodes, director of the Australian Child Health Poll, said it was the first time people had been asked about their biggest health concerns for children.

While the excessive use of electronic devices was expected to feature highly, Dr Rhodes said it was surprising to see lifestyle issues top the list.

Fifty-eight per cent nominated excessive screen time as their biggest health concern for children, ahead of 55 per cent who identified obesity and 54 per cent who identified a lack of physical activity.

"Screen time has been linked to a number of health problems in children," Dr Rhodes said.

"Research has shown that it is linked to sedentary behaviours which can lead to obesity. There is a lot of interplay with the modern lifestyle of children in our results."

The results of the poll are in contrast to a 2012 report into child health from the Australian Institute of Health and Welfare, which found asthma was the most common chronic condition among children and cancer the leading cause of death.

Dr Rhodes said respondents were asked to rank "traditional" health concerns but they didn't feature as highly in the results.

However, while a majority of people identified childhood obesity as a big health problem just 8 per cent of parents thought it was an issue for their own kids.

With one in four children overweight, Dr Rhodes said the poll results showed that some parents weren't recognising that their children might be at risk of obesity.

"There is research that shows people, for whatever reason, are less likely to perceive this problem in their own children, this appears to confirm that," Dr Rhodes said.

The poll results come amid growing concerns about the health risk of of excessive screen time for children.

A study of 9000 secondary school students by the Cancer Council and National Heart Foundation found teenagers were spending more time on phones, computers and tablets.

The report found 77 per cent of students were spending more than two hours a day using electronic media for entertainment, while 24 per cent were achieving the recommended 60 minutes or more of exercise each day.

Dr Rhodes said the poll gave a voice to the public's concerns about lifestyle issues and the impact they were having on childhood health.

"The pathway for health care is not clear because they are non-traditional problems," she said.

"Where do you go to find help if a child has an addiction to an iPad?"