Cosla said the time may be right to assess the scheme's affordability in an era of huge public spending cuts.

The concerns came after new figures showed the policy now costs £376m a year - double the amount of when it was first introduced in 2003.

Scottish ministers remain committed to delivering free care.

The government, which has increased funding for free care, said the policy, implemented by local authorities, was improving the lives of tens of thousands of vulnerable, elderly people.

But a Cosla spokesman, said: "Scottish government statistics demonstrate that the number of people in receipt of free personal care continues to grow, along with the overall cost of the policy.

"What is more, our ageing population means that the cost of free personal care will significantly increase into the future.

"As such, perhaps the time is right - amidst huge public sector spending cuts - to ask about the affordability of this policy into the future."

Under the policy, over-65s who live at home are not charged for personal care services, while those paying their own way in care homes get £149 a week for personal and £69 for nursing care.

The vast majority of extra costs are associated with caring for people in their own homes.

The figure came after a recent wide-ranging report suggested free personal care could become means-tested.

A Scottish government spokeswoman said: "Free personal and nursing care currently improves the lives of more than 50,000 vulnerable older people in Scotland.

"These figures show an increasing proportion of the people who benefit from this policy are being cared for in their own homes, reflecting our policy of supporting older people to remain independent in their own homes as long as possible."