Staff at Irish Life attached to the Unite trade union are to hold two days of strike action.
The action has been announced for December 17 and January 20 and is the escalation of four two-hour stoppages which have taken place.
A dispute has been ongoing since the beginning of November over a new pay model.
Unite, which represents the 1,200 staff, says the company is refusing to attend the Labour Court.
The union's Regional Officer Maeve Brehony accused Irish Life of forcing industrial action due their own intransigence in the dispute.
"Our members have worked to make Irish Life the respected and profitable company it is today, she said, "and they are not prepared to accept a situation where management unilaterally imposes a new pay model while deciding that it will negotiate collectively with some workers but not with others."
"It is up to Irish Life management to resolve this dispute by coming to the table and negotiating in respect of all its workers, rather than imposing unilateral dictats," she added.