Royal College of Nursing (RCN) Wales has rejected the latest NHS pay offer, meaning nursing strikes will go ahead despite acceptance from other unions.
The vote to reject the pay offer for NHS staff in Wales was rejected by RCN this week at a meeting involving all health unions.
The majority of health unions have voted to accept the Welsh Government's latest NHS pay offer. It means staff will have received more than 15.7% extra pay over two years.
But the RCN says it remains in dispute with the government.
The union says their planned days of industrial action on June 6, 7, 12 and 13 July will go ahead "unless the Minister for Health and Social Services reopens meaningful negotiations that value the nursing profession."
Helen Whyley, Director RCN Wales, said: “RCN Wales remains in a formal dispute with the Welsh Government over NHS pay after a majority of members rejected the pay offer.
“I have written to the Minister for Health and Social Services today, seeking to urgently re-enter negotiations, and unless that happens, members of RCN Wales will be on the picket lines once again from next month.
“I respect those in our membership and in other unions who voted to accept, but this was not the view of the majority of our membership.
She added: “The decision to take strike action is not taken lightly by us or our membership. Nursing is the largest part of the NHS workforce and they require an offer that matches their true value.
"The voices of nurses need to be heard once and for all, before the profession and patient care is depleted any further."
In response, the Welsh Government says it will continue talks to avoid further industrial action.
Eluned Morgan, Minister for Health and Social Services, said: "I am pleased that, overall, union members have accepted our offer and am grateful to all our unions for working with us in social partnership.
"I have therefore decided to implement the offer for all Welsh NHS Agenda for Change staff and Welsh Government will immediately begin the process for making the pay award so that workers receive the payments as soon as practicable.
"There are important non-pay elements in the accepted offer and we will begin discussions in social partnership to move to implementation without delay. We will be meeting NHS unions and employers at a regular partnership committee today where we will begin this discussion."
She added: "Two unions remain in dispute regarding the 2022-23 pay award and I do recognise the strength of feeling amongst members of all unions whether they voted to accept or to reject. While maintaining the collective agreement, we will continue discussions where we can in order to seek to address legitimate specific concerns and to avoid any further industrial action."