Irish workers are paying more tax today than they were a decade ago.
In a pre-budget submission, the Irish Tax Institute says take home pay for a single person on €35,000 is down by nearly €1,000.
Those on €75,000 take home 5% less than they did in 2008.
Meanwhile, Social Justice Ireland says most proposals for tax cuts benefit the better off more than lower earners.
Dr Sean Healy from the organisation says only two proposals would be fair for all.
He suggested: "If you were to reduce the lowest of the USC rates, everybody above €13,000 would benefit more or less by the same amount.
"The second option would be to increase tax credit, but that would basically ensure that most people would benefit."
However, Dr Healy also said that the Finance Minister should hold off on tax cuts in the next budget, arguing: "We believe that any available money should be used to improve Ireland's social services and infrastructure; to reduce poverty and social inclusion; and to increase the number of jobs for disadvantaged groups like people with disabilities and the long-term unemployed."