Welsh Conservatives say the Welsh Government has 'underestimated' how big a problem empty housing is creating. Shadow Housing Minister Mark Isherwood says there are 32,000 empty properties across Wales. The Welsh Government estimates there are 23,000.
He's calling for more to be done to bring those empty properties back into use.
Owners of empty properties in Wales could face an increased council tax bill.
Wales' Housing Minister Huw Lewis is considering introducing penalties, to encourage people to get empty houses back into use.
A Welsh Government scheme is currently funding the renovation of 5,000 empty properties.
Owain Phillips reports.