Amsterdam wants the transport ministry to step up its checks on the illegal taxi service Uberpop, the city council said on Wednesday.

Transport alderman Pieter Litjens will raise the issue in talks with junior transport minister Wilma Mansveld on Thursday.

So far, just 15 Uberpop drivers have been fined, even though the service has been ruled illegal in the Dutch courts.

Litjens told a city council meeting on Wednesday morning that licenced taxi companies must also uphold the law and make sure their drivers don’t take action against Uberpop drivers themselves.

On Wednesday it emerged five Uberpop drivers have made formal police complaints after being threatened by masked men with hammers and wearing knuckle dusters.