The figures, which will be used by Brian Cowen in framing the forthcoming budget, also show that well over half of the total tax take comes from 190,000 people on incomes of more than 60,000 a year.

At the other end of the income scale, more than half of the two million people in the tax net earn less than 25,000 a year and they contribute just 6% of the total tax take.

The Revenue statistics became available only last week even though they relate to the 2003 tax year. This means Cowen's budget arithmetic will be based on data that is three years out of date.

Economists have frequently blamed reliance on dated information for the way tax receipts have overshot budget estimates in recent years.

"Income tax projections are based on historical figures that are way out of date, " said Jim Power chief economist at Friends First. "Given the dramatic pace of change in the Irish economy and labour force, it is dangerous to use statistics that are more than one year old."

He added that the number of high earners is likely to have soared since 2003. "I wouldn't be too surprised to learn that only 50,000 people has six-figure earnings in 2003 but I'd be amazed if the number was the same in 2006, " Power said. "My guess is that the number of high earners could have trebled since then."

According to the Revenue's data, the 54,000 people on six-figure incomes are split almost equally between PAYE workers and the selfemployed. But the selfemployed outnumber wage earners by two to one on earnings scales above 150,000 a year.