ITV News has learned that local authorities across Wales are keeping most of their artwork hidden away in storage.
Freedom of Information requests have found councils own about 30,000 pieces of art - valued at £50m.
The figures come as local authorities face making cutbacks of millions of pounds, as they try to balance the books.
The body which represents Wales' councils said many pieces of art are kept in storage to ensure their security and preservation.
Councils play a vital guardianship role for the protection of public artworks and will obviously, wherever possible, seek to ensure that they are made available for public viewing and enjoyment.
Many works will however be kept in storage simply because this is the most sensible way of ensuring their security and their long term preservation.
– Welsh Local Government Association spokesperson
Local government in Wales does face growing and significant financial pressure when it comes to the funding available for local public services, but any sale of council owned artwork to raise extra funds for local services would need to balance this against the loss of the historical and cultural legacy that these artworks represent.
Cardiff Council, which has £36m of artwork - more than the rest of local authorities added together - said there are no current plans to sell its artefacts.
It said much of its artwork cannot be sold as it was given to the people of Cardiff in the form of bequests, and reiterated that the majority of items are on permanent display.
Conservative Shadow Heritage Minister, Suzy Davies, said there could be many pieces of artwork owned by Welsh councils that should be disposed of, or used elsewhere.
She said that, in a time of cutbacks to services due to squeezed budgets, "councils need to make the most of what they've got."
An ITV News investigation has found that councils in Wales own nearly £50m worth of art but the vast majority of it is not on display to the public.
Local authorities own over 30,000 pieces of art - but 26,000 of those are in storage.
Cardiff Council alone has £36m of artwork.
There are now calls for authorities to display more of the works, or sell them to generate money.