It is estimated that 5,000 people in Wales who are paying a spare room subsidy could - and should - have been exempt.
Under the rule, anyone who has been in their home since before 1996 and has continually claimed housing benefit does not have to pay the subsidy.
A spokesperson for the Department of Work and Pensions say they are looking at the issue carefully and will take any necessary action.
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What a lovely gesture by Martin Clunes and the cast of Doc Martin.
With all of the unsettled weather conditions over the next few days, pollen levels will remain low.
The rain will become lighter and more patchy towards midday, with a generally dry and brighter afternoon following.