Telephone companies which have been accused of overcharging customers - by applying a VAT rate which became effective from March 1st to calls made before that date - have insisted they acted correctly.
However, the issue, which was highlighted in yesterday's Irish Times, has led to calls on the companies to issue refunds.
Last night the Minister of State with responsibility for consumer affairs, Mr Tom Kitt, said the issue needed to be clarified.
The chairman of the Consumers' Association of Ireland, Mr Michael Kilcoyne, accused the phone companies of "ripping people off" while Fine Gael's spokeswoman on consumer protection, Ms Deirdre Clune, called on the companies to reimburse their customers.
Eircom, which has 1.2 million residential customers, insisted it had acted fairly while Digifone, which has 1.1 million customers, said it understood the new 21 per cent VAT rate had to appear on all invoices generated after March 1st, when the new rate became effective.
A spokeswoman for Digifone said the money collected would go to the Exchequer and it was therefore not Digifone's to refund to customers. Meteor, which has 100,000 customers, not all of whom were affected, said the company would clarify the position with the Revenue Commissioners. Esat Fusion could not be contacted for comment.
A spokesman for the Revenue Commissioners said it was the responsibility of the phone company which charged the "incorrect rate" to reimburse its customers.
"We consider calls not to be legally liable to the 21 per cent VAT rate until after March 1st," the spokesman said. He added that the Revenue did not have details of when customers made calls and therefore it would not be feasible for it to establish individual entitlements to refunds of VAT.
Spokesmen for the Minister for Public Enterprise, Ms O'Rourke, and the Office of the Director of Consumer Affairs said the issue was not one for them. They suggested it was a matter for the Office of the Director of Telecommunications Regulation.
However, that office said the issue was clearly a matter between the telephone companies and the Revenue Commissioners.
The controversy has arisen as a result of the telephone companies applying the new 21 per cent VAT rate, which came into effect on March 1st, to calls dating back as far as January, when they issued their latest bills.
The Revenue Commissioners said they "made it clear" to service providers "on numerous occasions" that calls made on or before February 28th should be charged at the old VAT rate of 20 per cent.
Mr Kilcoyne said what the phone companies did was "clearly wrong".
"I know they will argue that the money is going to the State but at the end of the day they are really overcharging people because they don't want to go to the trouble of charging people 20 per cent VAT up to the end of February and 21 per cent thereafter."