Homeowners in south Dublin are being "disproportionately" hit by the property tax, according to the chairman of the Oireachtas Budget Committee.
TD Josepha Madigan said areas like Roscommon do not face the same challenges as her own Dublin-Rathdown constituency.
South Dublin could be in for a major property tax increase when new valuations take effect in 2019.
Current rates are based on 2013 property prices and Fine Gael councillor for Rathgar-Rathmines Paddy Smyth says Dublin is being unfairly hit.
He said: "15% of the property tax from Dublin City Council goes to other areas.
"So, essentially, the people of Dublin are bing asked to put their hands in their pockets, just because we happen to live in properties that we've paid more for, where we've probably more negative equity, and essentially are subsidising a lot of the other constituencies."