The back-to-school effect is set to hit children with asthma - as just over half of the country's schools ring the first bell of the year today

The Asthma and Respiratory Foundation says asthma hospitalisations occur more frequently during weeks three and four of term one, than during the winter period.

It's encouraging schools to have emergency kits ready and for parents to ensure kids have inhalers.

CEO Letitia Harding says it's a change of environment when schools resume.

She says kids will be exposed to different allergens when they've been away from school for some time .. and some may have anxiety.