People take part in a rally in Trafalgar Square in support of striking NHS junior doctors, as the British Medical Association holds a 96-hour walkout in a dispute over pay, in London, Tuesday April 11, 2023. AP
Hopes had been high that nurses in England would accept the five percent pay offer brokered by the Royal College of Nursing (RCN) and the government in March.
But after putting the offer to its members, the RCN said 54 percent turned it down.
RCN members will walk out for 48 hours from 8:00 pm (1900 GMT) on April 30, with the action extended to staff in emergency departments, intensive care and cancer care units for the first time.
The refusal is a setback for the government, which had hoped for an end to the crippling health sector strike that has seen thousands of operations and appointments cancelled.
Hospital doctors below consultant level have this week been on a four-day strike demanding better pay and conditions.
Earlier on Friday, the Unison union representing healthcare workers overall, said nearly 75 percent of its members had voted to accept the same offer.
RCN general secretary Pat Cullen wants urgent talks with Health Secretary Steve Barclay and said the offer was "simply not enough".
"The government needs to increase what has already been offered and we will be highly critical of any move to reduce it."
She called for "significant action" to urgently address under-staffing and low pay in the publicly funded National Health Service (NHS).
"Until there is a significantly improved offer, we are forced back to the picket line," she added.
RCN members walked out for the first time in the union's 108-year history late last year, joining a wave of public and private sector workers calling for pay rises as inflation soared.
The government said the RCN rejection of the pay offer was "hugely disappointing" and said it was "fair and generous".
"The fact that the Royal College of Nursing has announced an escalation in strike action with no derogations, based on a vote from the minority of the nursing workforce, will be hugely concerning for patients," a health ministry statement read.
As well as a five percent pay increase in the next financial year, the offer included a one-off bonus worth at least £1,250 ($1,510) per person.
Two other unions representing healthcare workers have yet to announce the results of their ballot on the offer.
Healthcare bosses say further strikes would have an impact on reducing already lengthy waiting lists for treatment, which Prime Minister Rishi Sunak has pledged to reduce.