The bank’s parent, the Dublin-based AIB group, is cutting 2,000 posts by the end of next year.
AIB executive chairman David Hodgkinson warned the job losses would “spread widely across the group”.
The First Trust has 48 high street branches in Northern Ireland, employing 1,300 staff, but the AIB has said branch closures will be avoided.
“In some cases branch staff will have to slim down, but we are not looking at branch closure programmes,” AIB’s David Hodgkinson said.
The AIB group made an overall loss of £9.2bn last year. The job losses will result from the necessity to cut costs, it says.
First Trust’s losses of £680m included £5m transferred to the National Asset Management Agency, the Republic’s body that is taking over property loans to help shore up the banking sector.
The AIB’s operations in Great Britain made an additional loss of £501m – again with major transfers (£374m) to NAMA.
Overall the AIB group – the owners of the First Trust – made a loss of £9.2bn.
The AIB is more than 93% owned by the Irish state following a series of bailouts.