Four in five private landlords in the Netherlands rent out just one property and see the income as a supplement to their pension, the national statistics office CBS said on Monday.

Private landlords owned just 6% of the total supply of housing in the Netherlands – or 475,000 homes out of a total eight million residential properties, the CBS said in a survey of the housing market in 2018.

Rental housing, owned by housing corporations and investment groups as well as private landlords, accounts for 42% of the total housing market.

The CBS figures also show that 15% of the housing in Groningen is owned by private landlords, 13% in The Hague and 12% in Amsterdam.

City officials in the Dutch capital are planning to get tough on private landlords who, they say, are buying up properties and putting up rents so that it is impossible for  teachers and police officers to find a home.

For example, the city wants to bring in new rules to make sure that people who buy newly-built homes in the city actually live in them, rather than rent them out.