A slow drive by protesting police officers is causing considerable problems on some roads on Wednesday, Dutch media report.

The action involves a convoy of police cars driving at 60 kpm from Groningen in the north of the country to Maastricht in the far south. The convoy is occupying the full width of the motorways, causing traffic delays.

The police, who have not had a pay rise in four years, are taking part in the go-slow in support of their pay claim.

The ANWB motoring organisation expects the worst trouble to be later in the day when the convoy nears Rotterdam and then moves on to Noord-Brabant during the evening rush hour.

The convoy is expected to reach Maastricht around 19.30.

The police are also taking action on Thursday when police stations will close their doors for two hours. During this time no complaints will be processed, but officers will be available for emergency help.