Even though he is only 54 years of age, Goggin's entitlements are already so generous that the bank cannot put any more money into his pension between now and retirement. O'Donovan is the same age and, according to the bank's annual report published last week, his pension benefits are approaching the ceiling introduced by finance minister Brian Cowen in December's Budget.

The news is likely to inflame an already bitter dispute between the bank and trade unions over plans to shut the main pension scheme to new recruits from October. The row almost derailed the new national pay agreement at the last minute and unions have pledged to fight any move to water down the pensions of existing or new employees.

Goggin is entitled to a guaranteed pension of 606,900 a year when he retires. Because the capital value of this pension greatly exceeds the new 5m limit Cowen introduced on Budget day, Goggin's pension entitlements are now effectively frozen until retirement.

O'Donovan, who joined the bank from Aer Lingus in 2001, is in line for a guaranteed pension of 183,100 a year.

According to the annual report, the new 5m ceiling could have a "potential impact" on the amount the bank can contribute to his pension in the future.

Cowen introduced the ceiling in response to growing concerns that top executives and business owners were using generous pensions allowances to build tax-free wealth.

Cowen pledged to curb the entitlements of top earners, a move that would hit less than 1% of taxpayers, to help pay for more generous tax breaks to encourage pension saving among the lower paid.

Meanwhile, the annual report also disclosed that two top executives who retired from the bank during the year, John Collins and Roy Keenan, shared termination payments of almost 1.5m.

Collins was group development officer while Keenan was chief executive of the bank's operations in the UK. A spokeswoman said the payments were in line with the two men's contracts of employment.