RTÉ has been urged to reconsider its decision to shut down its longwave radio service at the end of the month.
Ireland's Catholic bishops said the loss of the service would mean fewer people would be able to listen to religious programmes.
They expressed concern that people living in rural areas and in Northern Ireland and the UK will be worst affected.
RTÉ said last week that only 2% of listeners to RTÉ Radio did so on longwave.
However, the bishops said that serving a marginal audience should be a priority for the national public service broadcaster.
They called on RTÉ to carry out a survey to determine the actual number of listeners to longwave broadcasts of religious programmes and how prepared those listeners are for a digital switchover.