A TD leading protests against the household charge is exempt from the tax because he lives in a council house -- despite his €92,000 salary.
SINN Fein's Dessie Ellis was among the first politicians to say he would not pay the charge last December.
However, the Herald can reveal that Deputy Ellis lives in a home provided by Dublin City Council and therefore does not have to cough up the €100. Such houses are usually reserved for families with far more modest incomes than €92,000.
Government sources told the Herald today that Sinn Fein were "a pack of hypocrites".
"The complaints of people like Dessie Ellis are all the more amazing given the fact that he is a tenant in social housing and Sinn Fein support property taxes in Northern Ireland," said a well-placed source.
"In the North, the Shinners don't seem too worried about house taxes that can be as much as €3,000 for some people, compared to the €100 we are looking for."
Finglas native Mr Ellis lives on Dunsink Road where he claims to pay huge rent to the local authority because his salary is means tested. But when questioned on the details of that arrangement, Mr Ellis said the rent he pays is bigger than a mortgage would be on the property.
"It's actually costing me more renting the house from the council rather than buying it because it's means tested. At the moment I'm not eligible for the household charge. I'm in a council house. But if we buy the house, which I'm in the process of looking at, that would change things.
"I'm paying nearly €1,000 a month on a council house. It's means tested, and I can't do anything about it at the moment because I'm in the process of seeing if we can buy it," he added.
Sinn Fein TDs only take home the average industrial wage of around €36,000 from their public salary -- but the rest goes into the party's own coffers rather than remaining with the exchequer.
"It's means tested on whatever money is coming into the house, and they (Fingal County Council) take it on my salary," Mr Ellis said, adding that it is the full TD's salary that is means tested, and not the industrial wage segment of it.
"They take it from the full salary," Mr Ellis explained. "I'm paying more in the long run than anyone else as a council tenant on a TD's wage. You're actually paying a huge amount. It's more than a mortgage would cost me, a lot more," he added.
On the household charge, Mr Ellis said the Sinn Fein position hasn't changed. "The policy with Sinn Fein is not to say directly to people 'don't pay it', but what we're basically saying is it's up to the individual.
"You see old people here and they have to pay €100 and they are living on an old age pension," he said.
"There's been people going to the post office, taking out their savings in coins and everything, the post office then say they can't take it and send them down to the council offices," he added.