The telecoms regulator is to investigate controversial new data roaming allowances proposed by the Irish mobile operator Three.
The new allowances would drastically reduce a Three customer's EU roaming data provision, even after an EU law on the abolition of roaming fees kicks in this June.
"We are aware that a mobile operator has recently informed its customers of new contractual arrangements that purport to draw a distinction between a contractual data allowance and an unlimited all-you-can-eat data 'service benefit'," a ComReg spokesman told the Irish Independent.
"We have sought information from the operator concerned so that we can assess whether the operator is in compliance with its existing obligations, as well as with the new roaming rules that will come into force on June 15."
It is the first time that the telecoms operator has commented on the controversy.
Last week, the European Commission criticised Three's plans.
"There is no loophole by which part of the domestic data allowance could be regarded as gift or side benefit and would therefore not count when traveling abroad," a spokesperson said.
This week, Irish Communications Minister Denis Naughten warned that ComReg and Irish mobile operators would be expected to adhere to the new European roaming rules.
"There are serious consequences for non-compliance," the ComReg spokesman told the Irish Independent.
"Over the past year, we have brought several criminal prosecutions, have imposed fixed penalty notices on operators and have taken other action to bring operators into compliance."
Three plans to offer as little as 1GB of roaming data on its plans after the roaming abolition law is introduced in June.
The company says that it cannot translate its 'all-you-can-eat' data allowances, which equate to 60GB, into roaming allowances because of onerous costs of up to €7.70 per gigabyte charged by other European operators.
But the European Commission has warned that mobile operators cannot partially implement the new roaming law.