Dutch and Belgian police raided addresses in Noord-Brabant, Limburg, Utrecht, and East and West Flanders on Thursday in a major case of international manure management fraud, the NRC reports.

Some 17 people were arrested in Belgium, and documents and property confiscated in a joint operation which included Europol and Dutch food watchdog NVWA.

The Belgian prosecution office said 24 farms, food companies and manure processing companies near Antwerpen had been raided, one of which is active in the Netherlands as well. Eight of the raids took place in the Netherlands.

The farmers and the companies involved are suspected of colluding to falsify figures about the amount of manure that is being transported and used on the land.

By manipulating the figures, the amount of phosphor and nitrogen are kept within the proscribed maximum, the Belgian prosecutor said, but in reality farmers are upping production by using more manure that is allowed.

A Dutch manure processing company is allegedly linked to a fraud involving organic waste.

The authorities said differences in legislation had made the cross border fraud easier to hide.

In 2017 the NRC reported that two thirds of manure management companies in Oost-Brabant and Noord-Limburg had been involved in some way in fraudulent actions. The largest manure management advisory agency Bergs Advies, in Limburg, is currently on trial for falsifying documents to help farmers duck manure regulations.