Vodafone and CIÉ Properties have been asked by Dún Laoghaire-Rathdown County Council not to go ahead with building a communications mast on the Dart line in south Dublin pending a planning investigation.
The mast, close to houses on Ardeevin Road and Sorrento Drive in Dalkey, is used by Iarnród Éireann for its own communications and is being replaced at present.
As part of a deal with CIÉ Properties, which owns the site, Vodafone is to build the mast and put a mobile phone transmitter on it.
Under the Planning Act, Iarnród Éireann does not need planning permission to erect masts needed in connection with the movement of traffic. But it is unclear whether it needs permission to include the Vodafone transmitter on the mast.
Other masts along the Dart, at Bray, Greystones, Malahide and Howth Junction, already contain mobile phone transmitters. Of the 41 Iarnród Éireann communications masts around the State, 36 have mobile phone transmitters.
The county council has said that it believes the attachment of mobile phone antennae to the existing signalling mast in Dalkey is not covered by planning exemption laws and that if work should go ahead, enforcement proceedings will be instigated.
Labour TD Eamon Gilmore said that it was wholly inappropriate that there should be an exemption for development of this type.
"The concept of exempted development was introduced in 1963 for emergency work and for statutory undertakings. The intention was to allow for the infrastructure of public services which were being developed,"
Mr Gilmore said: "The introduction of mobile phones was never envisaged at that time."
He said Vodafone and CIÉ "should have to apply for planning permission in the same way as local residents would to put an extension in their gardens."
Progressive Democrats councillor Mary Mitchell O'Connor said that the installation of the transmitter so close to private houses was a cause of concern. She called on the companies not to go ahead with the plan.
A county council spokeswoman said that CIÉ Properties had given an undertaking to cease the work and the council was pursuing the matter.
A Vodafone spokeswoman said that there had been no further work on the mast since the council had made contact with them.
