Young children who are exposed to too much screen time are more likely to develop physical and behavioural problems. (File photo)

Kiwi children who spend too much time on screens are becoming sicker, more obese, and more likely to be hyperactive, according to a new study.

Commissioned by the Ministry of Social Development, the study also showed young children who exceeded the recommended electronic screen time had poorer motor skills than those who were less exposed to the technology.

Researchers from Auckland University of Technology (AUT) and the University of Auckland analysed the development of more than 5000 children in the New Zealand-first study, using data from the longitudinal study Growing Up in New Zealand.

123RF Kiwi children spend an average of 1.5 hours on screens each day. The recommended amount for children under two is none. (File photo)

The researchers found two-year-olds who exceeded the daily screen time guideline of one hour each day were more likely to experience behavioural and health problems at about 4½ years of age.

Ministry of Health guidelines recommend no screen time at all for children under two years, and less than an hour a day for children between two and five years.

EKATERINA POKROVSKY Researchers say some screen time for children is OK, but parents should aim for no exposure to screens on most days. (File photo)

The study found children under two years spent an average of 1.5 hours a day on screens, increasing to two hours a day for children aged 3¾ years.

Report author Associate Professor Scott Duncan said those numbers did not surprise the researchers, but the significant health effects of too much screen time did.

"It's pretty clear that something negative's going on."

The researchers did not advocate for absolutely no screen time for children under two, but said that should be the aim on most days.

"It's one of those things that, as parents, again and again, we have to reprioritise. We can't just let it drift."

Other research had presented two theories on why too much screen time affected development, Duncan said.

One was that it replaced other activities such as playing outside, and the other was that young children could not deal with the amount of "one-way" information being presented to them.

Hamilton mother Charmaine Steyn allows her four-year-old daughter Maia no more than one hour of screen time every day.

Steyn said she wanted to instil a love of books into Maia because it encouraged imagination.

"That's why we never really had the television on. It's a rule that we had - no phones, no TV while she was awake when she was little.

"When she's awake, it's her time, we interact with her, we're reading stories, we're playing, and then when she's having her sleep time, that's when we can go on our devices."

Maia only became aware of tablets when she went to daycare after she turned two, Steyn said.

"She got to use it a couple of times, but because we found it caused some behavioural issues, we didn't allow it."

Plunket clinical leader Anne Marie Morris said children liked to copy adults around them, so parents had to take more care with their own screen time.



"As adults, we all probably spend a lot of time on devices and so probably the question we can ask ourselves as adults is: what is my role-modelling doing to what ... I teach the children around me?"