A major union has called for councils to be allowed to take over empty properties to house people on waiting lists.
The GMB's London region says landlords and foreign investors would be encouraged not to leave properties empty if they knew councils had the power to put tenants in them.
The union says local authorities should build more council homes at affordable rents, but meanwhile they should be given powers to use already existing housing stock which has been empty for prolonged periods.
The demand follows a study by the union comparing the number of long-term vacant dwellings – empty for at least six months – in each borough last year with numbers on waiting lists.
It found there were 22,481 long-term vacant dwellings in the capital, 2,244 more than the year before, while at the same time there were 232,409 households on local authority housing waiting lists.
The borough of Southwark had the highest number in the capital, 1,766, while it had 6,778 people on its waiting list.
GMB regional secretary, Warren Kenny, said: 'Property owners knowing that councils had such powers would be a big incentive for these owners to keep properties occupied.
'It would also reduce the incentive for overseas investors investing in buy to leave empty to do so.'