The charity wants the aids to be bought in bulk

At present, it said only 1.4% of people who need the hearing aids receive them and other people have been making do with outdated devices.

The organisation said this compares starkly with England and Wales, where by next year a third of patients could have access to the hearing aids.

The digital aids cost about �2,000 but the RNID estimates that with bulk NHS buying the devices could cost less than �100 each.

The charity's report "Scottish Audiology Going Digital" also pointed to "severe problems" in Scottish NHS services, with more staff and investment needed.

RNID Chief Executive, James Strachan, said: "Digital hearing aids have the power to revolutionise lives but modern hearing aids cannot be provided while audiology departments are being starved of cash.

"The robust evidence exists in England and Wales that patients benefit significantly - by more than 40% from digital compared to analogue aids."

A Scottish Executive spokesman said it was committed to driving up standards for all those affected by hearing impairment and has already commissioned a review of audiology services across Scotland.

The findings are expected in the autumn.