The national exam in Dutch as a second language has been postponed after details of the test paper were found on social media.

Education minister Ingrid van Engelshoven said in a letter to parliament that questions from past papers were being shared on chat forums by former candidates.

‘Candidates who know the questions have an advantage,’ she wrote. ‘That is not what we want. Everybody must be given an equal chance.’

The national exams authority CvTE said it was investigating how candidates were able to memorise details of the test papers so easily.

The written exam has been cancelled and rescheduled for January 1. Candidates who needed to pass the test to meet their integration (inburgering) criteria have had their deadline extended accordingly.

The other three elements of the test – listening, speaking and reading – are not affected.