A new study is suggesting stricter guidelines on how much recreational time children spend in front of screens like, television, computers and other devices.

It follows concerns by medical professionals of associated health problems like changes in blood chemistry, obesity, attention problems and reduction in sleep hormones.

The report by biologist and psychologist Dr Aric Sigman says the Government should come up with specific guidelines and parents should be informed.

"Not just in New Zealand but in many countries, there needs to be more linkage between the departments of education which always talk about more screen time - they see it as the future, and the department of health which sees screen time as a health issue."

He says a study in the last couple of weeks has also found found young people using screens in the evenings in their bedrooms, reduces sleep hormones.

"They need to fall asleep that evening and when you test their alertness the next morning it is down."

It's contained in a report commissioned by Family First.

Spokesman Bob McCoskrie says they wonder if it's time for New Zealand to put out more specific guidelines, as other countries are.

He says the report is critical of Government agencies' lack of guidelines for families.