Northern Ireland's largest trade union has warned an industrial fall-out is looming after thousands of public workers were ordered to switch off their workplace radios for good.

Both the Department of Social Development and the Department of Education and Learning have banned staff from listening to music and radios in recent weeks.

Civil service chiefs claim the move — which workers say came out of the blue — was necessary because workplace radios need licences from organisations that collect royalties for musicians.

But Brian Campfield, general secretary of the Northern Ireland Public Service Alliance (Nipsa), said the ban will lead to significant morale issues that will spark a reaction.

“This will lead to problems for the Departments because they will have a lot of disgruntled and demoralised staff on their hands, and that situation can't be allowed to continue for any length of time,” he said. “Even people in prisons are generally allowed to listen to the radio.”

Nipsa accepts tariffs have to be paid for workplace radios but Mr Campfield said taxpayer-funded departments should pay the necessary fees, particularly for workers carrying out repetitive tasks.

“A lot of the work that people in these areas perform can be quite monotonous and it's a long enough day without having some background music,” he said.

The Department of Social Development (DSD) said it will only purchase licences where there is a “business need”, usually for front offices or public areas, to keep customers entertained, as well as some canteens.

A spokesman was adamant their new policy was brought in to make sure it is keeping within the law. The DSD said it is now finalising licences with two copyright companies — the Performing Rights Society and the Phonographic Performance Limited — for 48 licences.

Despite requests, workers in offices not covered by these have been told they can not pay for licences themselves and have also been banned from listening to ersonal MP3 players during work.