Revenue has told Longboat Quay apartment owners they're not actually entitled to a cut in the property tax. A letter sent to some residents said they would only be liable for the Band 1 cost of €90 euro a year.
However the Finance Minister has revealed that letter was sent by mistake, and a follow up notice informed owners they must pay in full.
The local property tax is calculated based on the value of homes in 2013. Last year it was confirmed major fire safety works are needed to make the Docklands complex safe to live in.
That would affect the apartments' current market value but Revenue say there is "no basis in law" to make changes retrospectively. It means homes in Longboat Quay are liable for around €495 a year.
Sinn Fein's Dessie Ellis has asked Minister Michael Noonan to add the complex to a list of properties that are exempt from the tax, like those in ghost estates. He's stressed the need to act fast ahead of the general election, otherwise residents will have to wait until 2019 before the valuation can be changed.