Amsterdam council fraud investigators broke human rights legislation by secretly observing a man they suspected of wrongly claiming welfare benefits, the Parool reports on Wednesday.

A special court which deals with social security issues ruled officials overplayed their hand and broke the European treaty on human rights by following the man to work, the paper said.

The man said he worked 25 hours a week for a clothing manufacturer spread over five days a week. But officials suspected he worked more hours and followed him on 19 separate occasions. Their suspicions turned out to be true, but the evidence may not be used against him, the Parool said.

The court said the officials should have visited the premises at a moment the man was not supposed to be working rather than observe his behaviour from a distance.