The auditor general for Wales has reported that documenting the collections of the National Museum and Galleries of Wales could take 10 years.

Solving storage problems could take another 10 years on top of that.

Only about a third of the artefacts and art works are listed in computer records.

In total, the National Museum believes it could take 384 staff years to bring the collections up to date.

It argues that reassigning staff to deal with the problem may cause the service it provides to the public to suffer.

Sir John Bourn, the auditor general, said that the museum had tackled some of the criticisms that had been levelled at it since its last audit but stressed that he expected further improvements.

"The backlogs that persist mean that much of the collection is not maintained as well as it ought to be and that this needs to be addressed to preserve Welsh national heritage for future generations", he said.

"Until these are dealt with, the public cannot take the full advantage of all that the museum has to offer."

However, museum spokesman Robin Gwyn appealed for extras resources and warned that "you can't cut corners".

The museum estimates that it requires an extra £1.65 million over the next 10 years.