Many schools are breaking the law by demanding contributions from parents for summer trips and other extra services without making clear they are voluntary.

The law was changed last year to make it illegal for schools to exclude children from excursions because their parents had not paid their dues.

The average annual contribution is €57 but some schools ask for as much as €600 to fund overseas trips or bilingual classes which are not financed by government.

A survey of 120 secondary schools by Stichting Leergeld and newspaper NRC last month found that around half were still insisting or implying that the contributions were compulsory or making participation dependent on paying them.

Education minister Dennis Wiersma said he would be writing to all primary and secondary schools about the ‘unacceptable’ situation.

‘I think it’s very unfair and undesirable if schools don’t make it clear to parents that the voluntary parental contribution is genuinely voluntary and that children can no longer be excluded from extracurricular activities if parents don’t pay. ‘The law requires schools to state this explicitly in their handbooks.’