Ireland could get a second, much bigger interest rate reduction on the €22.5bn it has borrowed from the IMF after it was identified by a leading economist.

Karl Whelan, professor of economics at UCD, had already calculated that a technical reorganisation of member countries' quotas had led to a small reduction for Ireland in the interest rate on the loan from the Washington-based fund since it was agreed in late November.

But Ireland will likely benefit from a much deeper cut when a large increase in the IMF's lending capacity is implemented next year.

The interest rate at which the Irish authorities borrowed from the IMF over three years had fallen by about 20 basis points, or a fifth of a percent, since November, Whelan told an Oireachtas committee last week.

But new information about an IMF reorganisation suggests the loan rate could fall by a further 0.5%, he told the Sunday Tribune.

The prospect of lower interest rates on the €22.5bn borrowed from the IMF may boost attempts by opposition politicians to renegotiate lower rates on the €45bn Ireland has borrowed from two European bailout facilities and EU nations.

However, international analysts say current interest rates as high as 6.5% on the €45bn would need to fall to 3% or 4% to significantly boost Ireland's creditworthiness.

"It may require a change in attitude from Germany to provide significant reductions on loans to Ireland. On the face of it I would not imagine they will turn around and lend at 3%," said Ben May, European economist at Capital Economics.

Meanwhile, markets continue to suggest there is a high probability of Ireland defaulting on its sovereign debts.