Negotiations have begun between management at AIB and unions representing workers at the lender over its plans to cut its workforce by up to 1,500 staff.
Last year the bank announced it aimed to reduce the numbers it employed as part of its three year plan using natural attrition, retirements and a voluntary severance scheme.
But in March it was forced to put the process on hold due to the impact of the Covid-19 pandemic.
Today the Financial Services Union (FSU) said formal consultation between the two sides had begun, despite its preference that they be postponed further.
"The FSU firmly believe that any proposals from the Bank to cut the workforce in AIB should be postponed and should only be tabled for discussion post Covid-19," said Billy Barrett, FSU Senior Industrial Relations Officer.
"The bank's decision to proceed is disappointing, however, formal consultation has now commenced".
The union said it was entering the talks with a clear agenda of minimising job cuts and serious issues have to be addressed as part of the discussions.
As part of the revised plan announced in December, AIB said it will be exiting its commercial banking operations in Great Britain, leading to the majority of the jobs there being under threat.
"The decision to wind down most of the bank's operation in the UK leaves many unanswered questions," Mr Barrett stated.
"The viability of the bank's remaining operation in the UK, the selection process for possible redundancies and the possible application of transfer of undertaking protection of employment law legislation are issues to be discussed."
The FSU said it was also seeking to ensure that proposed redundancies are real redundancies and that remaining staff are not shouldered with the burden of increased workloads.
"We will not accept the loss of full-time positions in AIB and have these replaced with precarious contracts," stated Mr Barrett.
The bank also aims to merge five overlapping branches as part of the plan and exit three buildings in Dublin over the next three years as leases expire.
AIB is not alone in seeking to reduce its headcount.
Bank of Ireland is targeting 1,400 jobs cuts over the coming years, while Permanent TSB announced in November that it plans to shed 300 jobs.
Ulster Bank is also expected to outline next week the outcome of a strategic review of its operations in the Republic of Ireland, with a complete withdrawal from the market reported to be among the options on the table.