Just one in four Dutch secondary school playgrounds are officially smoke-free zones, according to new research by asthma research group Longfonds.

The organisation will present the results of its research to junior health minister Martin van Rijn on Monday. It hopes the report will stimulate the minister to ensure smoking is banned in all schools. Half of all smokers had their first cigarette in the playground.

The research found most schools would like to be smoke-free zones but don’t take action because of opposition from staff and pupils. The Longfonds has drawn up a step-by-step plan to help schools make the switch.

The cabinet is planning to increase the age at which people can buy tobacco products from 16 to 18 from January next year.