Population changes caused by returning Irish emigrants and the arrival of foreigners will not significantly slow the ageing of Ireland's population over the next 30 years, the Central Statistics Office has said.
The CSO claim causes difficulties for the Labour Party, which has argued that Ireland's demographics meant that it could reduce National Pension Reserve Fund contributions for five years to fund new hospitals.
Yesterday, Fianna Fáil's Minister for Social, Community and Family Affairs, Mr Dermot Ahern said the existing 1 per cent of GNP contribution was "vital" because the Exchequer Pensions Bill would jump to 8.1 per cent of GNP by 2026.
"That's an awful lot of money down the line.
"Such borrowing would prove detrimental to our economic wellbeing and Fianna Fáil will simply not let it happen," added Mr Ahern.
The Central Statistics Office pointed out that the number of over-65s will rise to 767,000 by 2026 from a little over 413,000 today.
In recent years, 50,000 people a year have come to live in Ireland, though the percentage of these who are returning Irish emigrants has begun to drop in the last couple of years, said the CSO.
In addition, the returning Irish tend to have smaller numbers of children: "They tend to have adopted the lifestyle of the countries in which they lived when they were out of Ireland," said a CSO spokesperson.
Irish fertility rates, though still the highest in Europe, are below the key replacement figure of 2.1 children per couple. Currently, the Irish pregnancy rate stands at 1.89, while the EU average is 1.75.
Even the current rise in pregnancy rates will not last long, according to the CSO, since the figures are being boosted by pregnancies of women born during the last baby boom, between 1975 and 1980.
Despite fears that immigrants are choosing to have children to take advantage of Irish citizenship law, the CSO has found that immigrant couples tend to have fewer children here than they would if they were in their home countries.
"I don't think that immigration fertility rates will make an appreciable difference. They would have to have huge fertility rates to do," the CSO official told The Irish Times.
The Labour Party had used OECD figures to rebut Fianna Fáil's claim that Ireland is facing "a pensions timebomb" like EU counterparts.
In 2000, 2.9 per cent of Irish Gross Domestic Product was spent on pensions. In 2010, this figure will drop to 2.6 per cent ; by 2020 it will rise marginally to 2.7 per cent, and in 2030 it will go back to 2.9 per cent of GDP.
"This compares to increases in Germany of 6.9 per cent of GDP between 2000 and 2040, and 8.8 per cent for Italy in the same period," said a Labour Party adviser, adding that Italians' pension costs would consume 21.4 per cent of the country's GDP by 2040.
Producing a table from an actuarial study carried out last year for the Department of Finance, Labour said index-linked pensions costs would drop from 3.4 per cent in 1999 to 2.8 per cent of GDP in 2026.
"Labour's position on the National Pension Reserve Fund is that we believe the extent of the demographic 'time bomb' in Ireland to be significantly less than in other OECD countries.
"While we favour the principle of the fund, and wish to maintain it, we believe that there is a need for flexibility in how it operates, particularly with respect to the annual contribution," said a briefing paper.
