Funding ring fenced by Cardiff council for emergency respite for carers looking after family members has not been used over the past year.
Out of a total of £159,132 put aside for carers' services, breaks, and emergency respite, only £39,228 has been spent.
In 2009 the Health, Social Care and Wellbeing department of Cardiff Council campaigned for more funding for respite care, and eventually received £50,000 extra.
Tony O'Shaughnessy, 45, a university lecturer in Cardiff whose 81-year-old mother has dementia and needs permanent care said: "Anyone who has cared for someone knows that it is really difficult and having a break is really important.
"I would have thought that carers would have made good use of the council's money and I'm surprised it hasn't been used."
"My mother is actually in Knowsley, near Liverpool, and I know the council there provide my step father, who looks after her most of the time, a week's break every eight weeks and she also goes to a day centre three days a week."
Councillor Ralph Cook, chairman of the adult services scrutiny committee, said: "One of the main problems with emergency respite care is that at any one moment you don't know how many beds you will need for the person who needs the care.
"So you have the choice of block booking beds, which means potentially wasting bed space for others who also need it, or not having any provisions.
"The reason the money isn't being spent could be about publicity of the service, or it could be about lack of need.
"The scrutiny committee have asked the Health, Social Care and Wellbeing department to write us a letter explaining why the money has not been spent."
Posy Akande, Carers Representative for the Health and Social Care Wellbeing department, and who cares for her husband who has dementia, says: " I run a weekly stall where carers can come for advice.
"Other carers come to me saying they are at breaking point.
"What is important is having that little light at the end of the tunnel, and that's why respite care is so important."