Some 20,000 people have rang the Revenue Commissioners’ helplines since Friday seeking clarification on their pension liabilities.
Up to 12,000 calls were received on Saturday with a further 8,000 on Friday. A spokesman for Revenue was unable to say how many calls were received today.
Revenue opened the special helplines to help deal with an expected flood of queries from pensioners concerned about additional tax that may be due on their pensions this year.
Retired people with large private pensions are likely to be pursued for arrears where it is found they underpaid tax due on their State benefits, the Revenue Commissioners said.
Some 150,000 pensioners received letters, after Revenue received detailed information from the Department of Social Protection about pension payments for the first time.
Taoiseach Enda Kenny today called for clarity to be brought to the matter and said he accepted the letters had caused "confusion and anxiety."
"It is essential that everyone knows where they stand in relation to tax compliance. The Revenue need to provide clarity to pensioners who've been told they're liable for more tax."
This morning Minister of State with special responsibility for Housing and Planning Jan O'Sullivan said pensioners need to be reassured that the Revenue Commissioners won't go after them for back tax.
Speaking in Limerick, Ms O'Sullivan admitted "mistakes have been made" after the tax man sent out the letters to elderly people last week looking for increased taxes.
"Well I think there are lessons to be learned. I think there may have been mistakes made, in fact, that people got letters who didn't have an obligation.
“I believe that elderly people in particular are very careful about how they pay their bills, about how they balance their income and make sure they can afford to pay what they have to pay, and for those reasons they would have a got a shock if, first of all, they were told they had a tax liability for the future - I think people would deal with that- but then to be told they might owe back money, I think was what really frightened people."
Ms O'Sullivan added: "They do need to be reassured, they do need to be told exactly what their own personal situation is, and, by and large, I believe the Revenue won't go after people for back tax."
"I think we do need to learn lessons for the future, particularly maybe to approach it by saying to people, they may or may not have a tax liability - 'where this is a new system we've got information from the Department of Social Protection and were trying to clarify people's liabilities' - I think that might have been a better approach but, certainly I hope lessons will be learned from this," the Minister added.
Senior officials from the Revenue Commissioners will be asked to explain before an Oireachtas committee this week why it sent letters seeking payment of extra tax from pensioners who in many cases have no tax liability.
Revenue chairwoman Josephine Feehily and officials from the Department of Social Protection will face questions from TDs and Senators at what is likely to be a robust meeting of the Oireachtas committee on finance on Wednesday. The handling of the issue has also sparked a political row about whether the Government knew in advance that pensioners would be targeted for tax in this way.
Fianna Fáil finance spokesman Michael McGrath said the move formed part of last month’s budget strategy, but Ministers chose not to tell older people, to avoid criticism.
“The Government made a political choice not to reveal the details of the initiative at budget time and instead allowed the Revenue to scare the living daylights out of thousands of pensioners around the country this week,” Mr McGrath said.
A spokesman for Minister for Finance Michael Noonan last night rejected the criticism.
He said it was public knowledge that an additional €45 million would be raised as a result of a data-sharing exercise between the Revenue and the Department of Social Protection and other agencies. However, he said the Government did not have a role in the “operational” aspects of how the data would be analysed. This, he said, was a matter for the Revenue.
The Revenue has been fielding thousands of phone calls from worried older people about their pension liabilities.
However, in many cases, older people who are fully tax-compliant received letters seeking payment.
Speaking on RTÉ Morning Ireland today, Revenue spokesman Declan Rigney said his office needs to “look at” how the situation was handled. "We are due to meet with various representative bodies over the course of the next few days we will talk to our customer panels as well,” he added.
Revenue has defended its decision to communicate with taxpayers directly. It said public information campaigns did not work as well as individually tailored information.
It also defended sending out the letter in January, because this would allow the tax liability to be spread out over the entire year.
The Revenue Commissioners’ helplines will reopen again today. The number for callers in Dublin is 1890 333 425. People in Cavan, Donegal, Galway, Leitrim, Longford, Louth, Mayo, Monaghan, Offaly, Roscommon, Sligo and Westmeath can call 1890 777 425 while those living in Clare, Cork, Kerry and Limerick can call 1890 222 425. People living in Carlow, Kildare, Kilkenny, Laois, Meath, Tipperary, Waterford, Wexford and Wicklow can call 1890 444 425.