The Royal College of Nursing said its members would walk out on June 6 and 7.
But the union has agreed a number of exemptions, including cancer care, critical care and some children’s services.
And it said it will also staff a number of services on “night duty levels”, including emergency departments and community care.
It comes after union members rejected the Welsh Government’s revised pay offer in May.
However, because the deal was accepted by the majority of other unions, the Welsh Government implemented the deal.
The Welsh Government has said the average pay award for NHS staff in Wales – apart from doctors, dentists and senior managers – is 15.7% over two years from 2022/23 and 2023/24, 11.2% of which will be permanently in pay packets with the rest made up with one-off payments.
The RCN said the pay deal “does not go far enough to reward nursing staff fairly and support them with the spiralling cost of living” as it announced that strike action on June 6 and 7 and July 12 and 13 will go ahead as planned.
The union has called on the Welsh Government to reopen negotiations.
