Over 600,000 Saorview consumers have been urged to retune their set-top boxes and digital televisions or risk losing their television service.

The request to householders comes a year after RTÉ’s analogue signal was switched off and replaced by free digital terrestrial television service Saorview

The change required by viewers of the State's free television service is to allow the introduction of high definition by RTÉ in the New Year.

Saorview has said while viewers will not notice any significant change to the programme guide or additional channels, a failure to rescan will result in eventual loss of service.

“Your box isn’t smart enough to know where to find that channel itself. By doing a simple retune you will tell your box to go and look for the new channel,” Saorview digital reception manager Brian Geraghty said today.

The rescan of the channels can be done from today and over the next three weeks. It will be “very straightforward” for most people and takes “five minutes”, he said.

He noted that a similar channel tune was something many people would have done when installing the service last year. They should pick up the Saorview remote control for the set-top box or television, go to the installation menu and do a rescan or retune, he told RTÉ Radio.

Even consumers without high definition televisions will need to carry out the rescan, he said.

Consumers have about three weeks to scan their boxes so there is “no panic” Mr Geraghty said.

He said the Saorview switch-over from analogue had been a “huge success” with over 600,000 households using it in at least one room.

Instructions for a rescan are available on the Saorview website. Anyone with problems can contact the Saorview helpline on 1890 222012 or email info@saorview.ie.