Local Property Tax has been a success story for the Revenue Commissioners since its introduction in 2013.
But despite achieving a 96% compliance rate the agency is now moving to crack down on homeowners who 'significantly undervalued' their assets when self-assessing three years ago.
They became suspicious after some 15% of homeowners submitted a higher valuation for their home then the one originally provided in the 2013 estimate.
It is thought those homeowners might have been moved to come clean because they wanted to sell their houses in an improved property market.
Director of Taxation at Chartered Accountants Ireland, Brian Keegan told Newstalk.com's Breakfast Show the property tax is not a 'fair tax' and is not attempting to be: "Revenue's focus up to now was getting everybody into the net first of all and then making sure what's in the net is a big enough fish."
The most important thing to note about valuations is that they are frozen until late 2016.
Brian Keegan told Breakfast that if your initial valuation was honest, no matter what changes have occurred to your house in the meantime, you are in the clear.
The crackdown comes amid speculation that government may move to freeze the payment bands for a further two years, until 2018, because of the upcoming election.
The property payment bands were based on recommendations made in the Thornhill report in 2012.
As it stands, the first band covers all properties worth less than €100,000. Thereafter, the bands increase by increments of €50,000.
It was up to individual homeowners to confirm the band they belonged to, when in May 2013 Revenue sent them a letter suggesting what they might owe.
Revenue says if your assessment then was an honest one, you can rest assured you are in the clear.
Breakdown of property tax bands from Revenue
Under the original tax bands people paid roughly €180 per €100,000 of value in their home.
Chart shows the band changes homeowners nominated themselves for Via: Revenue
But lots of homeowners have opted to change the bands their homes sit on since the tax was introduced. Of those who changed, 15% increased their payments; 8% increased by one band, 3% by two bands and 3% by three or more bands.
That is thought to have sparked Revenue's curiosity.
Property tax is just one of a slew of new charges workers and homeowners have been hit with. Faced with that reality, an incredible 14 local authorities have chosen to reduce the rates set nationally.
That means, in spite of this crackdown, you could pay less this year than last year or even the year before.
If your local authority is one of the ones that reduced its rates you do not need to take any action, the amount you are charged will automatically change.
14 local authorities have reduced the rate of property tax they charge
Nearly 61,000 people are having compulsory deductions from their wages or pensions.
That is an uncomfortable reality for a government facing into a general election.
There is peculation that the government may put a cap or a freeze on Property Tax from 2016, when the current freeze is due to end.
Earlier this summer Michael Noonan, Minister for Finance, said there would be no 'sudden shocks' in relation to the property tax.
And last Spring the Tánaiste indicated a cap could be on the cards when the three year freeze expires.
The tax brings in about €500 million a year, a relatively small amount of money.
The Minister has appointed a commission to investigate how the rules might be adjusted to ensure people are not hit with bills they cannot pay when the freeze ends in 2016.
The government's plans will become clear when the details of October’s budget are revealed.
In the meantime, Brian Keegan of Chartered Accountants Ireland is advising any homeowners with concerns that they may be under-paying to "be proactive and make contact with Revenue" themselves.