AIB staff who live in Northern Ireland but work in the Republic of Ireland have been told they cannot work from home.
In a policy document issued to staff, the bank said that employees of AIB ROI may live in Northern Ireland but that "strict conditions apply".
Staff must "physically attend work in the jurisdiction where you are based for your full working week" according to the document.
"Working from home is not permitted," it added.
The document outlines a number of conditions including that employees must maintain an accurate home address in the AIB HR system and keep their tax affairs in order in both jurisdictions, including timely personal tax returns.
"Any failure to comply with these conditions will represent a serious breach of both this policy and the Code of Conduct, and will lead to referral under the Disciplinary Policy which may result in disciplinary sanctions up to and including the termination of your employment," the policy document states.
An AIB spokesperson said there is an onus on the bank to remain tax compliant.
"We have clear rules on the working location for employees of our Republic of Ireland business who live in Northern Ireland," AIB said.
"Employees of our Republic of Ireland business who live in Northern Ireland must work in our Republic of Ireland locations," the bank said.
"In order to comply with our tax obligations under current tax laws we are not in a position to facilitate them in working from their home in Northen Ireland," the spokesperson said.
Last month, members of the Financial Services Union (FSU) in AIB voted overwhelmingly to reject new hybrid working principles proposed by the bank.
The issue was referred to the Workplace Relations Commission (WRC) for conciliation.
In July, AIB said that staff would be required to work in an office-based location for a minimum of three days a week.
At the time, the FSU accused the bank of acting unilaterally and described the announcement as regressive, shortsighted and without justification.
Following negotiations between the two sides, AIB presented the FSU with new proposals including usage of AIB hubs, reviews of pre-existing arrangements, and a commitment to agree any future changed with the union.
Those proposals were rejected in the ballot of FSU members.
