The number of mobile phone masts has tripled in the past six years as firms upgrade their networks to supply new services.
Figures released by the Commission for Communication Regulation (ComReg) yesterday show there are now 5,181 sites hosting mobile masts.
This is a three-fold increase on the 1,656 sites hosting mobile transmitters in 1999, when there were just two mobile firms operating in the Republic.
ComReg released the statistics to The Irish Times in response to criticism in an Oireachtas report published yesterday, which said it was "not acceptable" that the regulator could not provide exact data on the number of masts.
A report, Non-ionising radiation from mobile phone handsets and masts, which was published by the Oireachtas committee on communications, recommended that responsibility for monitoring masts should be transferred to the Radiological Protection Institute of Ireland.
This agency should be provided with additional staff and expertise to enable it to monitor the emissions of non-ionising radiation from mobile handsets and masts, the report said.
All mobile masts and handsets emit non-ionising radiation, a type of radiation that uses low power to transmit energy. Several international reports into mobile phone handsets and masts have not found conclusive evidence it damages health.
The Office of Public Works has signed 32 contracts, expected to be worth €400,000, to erect antennae on public buildings.