Almost £17m has been lost
The body responsible for rates in Northern Ireland has defended itself after it emerged £17m has been lost through non-payments.
Some 30,000 properties, listed vacant by the Land and Property Service, were, in fact, occupied but rates bills had not been issued.
The mistake came to light following an inspection of the vacant premises.
Trevor Steenson of the Land and Property Services said a lack of resources led to the mistake.
"It (the service) couldn't do it with the resources that it had available at the time and that's why we entered into partnership with the local authorities and why we instigated this project," he said.
"The Land Property Services has put additional services into that unit and certainly from now we will have the resources that we need to properly investigate vacant properties."
In Belfast, 13,000 premises thought to be vacant were surveyed. More than half were found to be occupied.
BBC NI Business Correspondent Kevin Magee said that about 6,500 properties in the city which were thought to be vacant are, in fact, occupied.
So far, the majority of people living in them have not been billed for rates.
It is thought that this could cost Belfast City Council almost £2m in lost revenue in the next year.
The SDLP group at City Hall said the council should be compensated for what it described as the "incompetence" of those charged with collecting rates.