Irish Life employees represented by the Unite trade union are to hold two one-day strikes on 17 December and 20 January next.
The dispute centres on the company's attempt to introduce a new pay system. However, Unite is also accusing management of refusing to engage with the union to represent a cohort of senior staff who they say want to be represented by the union.
The union has already held four two-hour lunchtime stoppages, but said this escalation was forced on workers by what it described as "management intransigence".
Unite says it represents nearly 1,200 Irish Life workers in Dublin and Dundalk, two thirds of whom backed the escalated strike action.
Union official Maeve Brehony accused management of a coordinated strategy of intimidation, and of trying to "substitute so-called focus groups for collective negotiation".
She said Unite was particularly concerned about warnings from management that if members voted to escalate action, they would maintain sales targets - resulting in non-payment of sales-related pay.
She claimed the company had also said it would withhold attendance payments from some of the company's lower paid workers, who relied on such payments to bring them closer to the Living Wage of €11.50 per hour.
Ms Brehony urged Irish Life management to resolve the dispute by coming to the table and negotiating in respect of all its workers.
Irish Life has previously accepted that it has traditionally engaged in collective bargaining with Unite on behalf of 650 clerical personnel.
However, it notes that the majority of the firm’s 2,300 employees are specialists and managers who have always had annual pay reviews based on individual performance and market rates - without collective bargaining through a union.
It said the company has already committed minimum salary increases for this group of between 1% and 2% from 2016-2018, as part of the transition to the new performance based system.
Irish Life accuses Unite of seeking to change the long-established mechanisms for pay reviews for specialists and managers who have not previously been covered by collective bargaining on pay.
The company confirmed it was prepared to go to the Labour Court - but only to discuss the pay of the 650 clerical employees.