The Government is making final legal preparations to allow it tax bank bonuses at 90pc following furore late last year over planned payments at AIB.
The measure was scheduled to be included in the first draft of the Finance Bill published yesterday, but Finance Minister Brian Lenihan said it would be introduced in the "later stages'' of the bill.
It is understood the department wants to introduce a watertight legal measure to halt payment of bonuses for work done in 2008.
The Government is facing pressure because the measure appears to involve taxing bonuses retrospectively. But it is understood the Government will argue that the period when the bonuses are actually paid is the crucial one.
AIB staff would be the main beneficiaries of any bonuses, although a smaller number of Bank of Ireland staff have also got bonuses over recent months and an investigation is under way into how many payments its staff received, or are due to receive.
Labour Party finance spokeswoman Joan Burton has asked Mr Lenihan to outline how many bonuses were paid in Bank of Ireland and to how many staff. It is understood large bonuses have been paid to senior executives at Bank of Ireland Asset Management, which is now owned by US bank State Street.
In December, it was revealed that over 2,000 AIB staff were due to be paid bonuses for work done in 2008. Most of the staff are understood to be from the capital markets division.
Ironically, the bonuses are for work done in 2008 when the bank came close to collapse before the Government stepped in.
A number of AIB staff are still taking legal action in the courts over the issue.
But before Christmas Mr Lenihan argued that a "supervening event'' had occurred and the bonuses could no longer be paid in the normal way. He said this event was the effective collapse of the bank and its recapitalisation by the Government.
Lawyers are split over whether this argument would be accepted by the courts.