Businessmen trying to attract people to a Christian lifestyle are taking legal action to force RTE to screen their adverts.
The adverts had been accepted by British-based broadcasters that can be viewed in Ireland. Campaigners argue that RTE TV had initially accepted them but then turned them down after legal advice.
Under broadcasting laws, TV or radio stations cannot carry commercials dealing with the merits of a particular faith or belief.
The "Jesus gives you power to change" campaign is being backed by a group of businessmen from three different churches.
The 1.8 million campaign, aimed at people on both sides of the border, comes at a time of falling church attendance after a series of scandals in recent years.
Campaign spokesman Mr Stuart Kenny said the adverts, due to start on Monday, are the linchpin of their mass-media drive.
A spokesman for RTE said they had initially cleared the copy for the advert but had had not given final approval or accepted payment.
"After taking legal advice we believe we are precluded from taking the advert."
Mr Kenny said the month-long campaign was aimed at explaining "who Jesus is, and what he teaches, and what benefits there are in accepting him and walking with him."
Among those who will feature in the campaign is German golfer Mr Bernhard Langer, who describes how religion has filled a void in his life.
AFP