Between 10% and 20% of rent controlled properties owned by big housing corporations in Amsterdam may be illegally sublet, the Financieele Dagblad said on Wednesday.

In total, 186,000 properties in the capital are set aside for low income households and research by the paper shows that tens of thousands of official tenants may be committing fraud.

The paper and research group Decisive Facts studied adverts on the popular housing rental site Kamernet and compared with them with the corporations’ own housing stock. It found large numbers of corporation houses were being rented out via the website, often for two or three times the legal rent.

The scale of the fraud is adding to the pressure on the city’s housing stock, where just 3% of corporation housing is freed up for new tenants every year. The waiting list for a rent controlled property, with a rent of less than €720 a month, is now 14 years.

Hester van Buren, chief executive of the Rochdale housing corporation, told the paper that housing fraud is often committed in combination with social security fraud and other problems.

Housing corporations need to work together with the police, tax office and SVB benefit payments agency to properly combat fraud with social housing, she said.