Higher earners pay more in tax in Ireland than in Sweden, the UK, Switzerland and the United States, a report will show today.
The Irish Tax Institute's Budget Tax Study claims a worker here earning €75,000 pays around €796 more in personal tax than an employee in Sweden, a massive €6,136 more than our neighbours in the UK, and €1,237 more than Spanish workers.
A worker on €75,000 is categorised as a high earner and is above the Coalition's classification of a middle-income earner on between €33,800 and €70,000.
However, the finding that Ireland is above Sweden will be greeted with surprise, as the Scandinavian country is viewed as a high-tax economy.
Taoiseach Enda Kenny has pledged to slash the marginal rate of tax to below 50pc in next month's Budget and has said he will also target the controversial Universal Social Charge (USC).
Ireland's marginal tax rate of over 50pc was the ninth-highest in the developed world last year, behind the likes of Portugal, Belgium, France and the Netherlands, the report said.
It added that Ireland's marginal tax rate rises to 55pc for anyone self-employed earning more than €100,000.
It has been speculated that the Government is looking at the possibility of cutting the rate of the USC by 1.5pc.
The Tax Institute said such a move would save those earning the average wage of around €36,000 about €280 a year; while those on €75,000 would gain around €787 per year.
It estimated that lowering the 7pc USC rate by 1pc would cost the exchequer €364m, but more than half of taxpayers would benefit.
Irish Taxation Institute president Mary Honohan will deliver the findings of the study at a briefing this morning. The institute produces a comprehensive tax analysis ahead of the Budget each year.
The figures compiled by the institute include taxes, social security payments and other State deductions from wages.
The big factor pushing up tax bills in Ireland is the low entry point to the marginal rate of tax, which is also very high.
The Government has repeatedly said that cutting personal tax would stimulate the economy and attract emigrants home.
At a dinner organised by the business lobby group Ibec last week, Mr Kenny said the current high rate of 51pc is penal and bad for recovery.
The Taoiseach also pledged to bring unemployment down to 6pc over the lifetime of the next government.
Laying out his pre-election stall, Mr Kenny said the Government would ensure that it would make work pay through a combination of cuts in the rate of tax on work, better and more affordable childcare, and a higher minimum wage.
The Government plans to include incentives in the Budget aimed at luring emigrants back to Ireland.
The Taoiseach has repeatedly signalled his intention to introduce measures to encourage many of the more than 200,000 young people who left the country at the height of the recession to return.
Mr Kenny said during the summer that emigrants are not coming home because they fear they will get "screwed" for tax.
As a result, it was widely expected that Finance Minister Michael Noonan would use Budget 2016 to make a direct plea to those people.
The Government has examined the possibility of rolling out a tax incentive for those considering returning home.
However, officials at the Department of Finance are concerned any specific tax measures aimed at ex-pats could antagonise taxpayers who stayed at home and worked through years of austerity.
A Government source said: "It doesn't look like we can introduce a tax incentive as it wouldn't be fair on people working here.
"We still want to do something for emigrants but it hasn't been decided what is possible at this stage."
Budget talks will intensify this week as the Dáil returns from the summer recess.
But the tax study findings will reiterate the concept of Ireland being a high taxation economy.