Downing Street has said it will not make an improved pay offer to nurses, after its previous deal was rejected.
The Royal College of Nursing (RCN) is set to return to the picket line, with strikes potentially lasting until Christmas.
The government offered a 5% pay rise this year and one-off a cash payment for last year, but members of the RCN voted to reject it.
Rishi Sunak’s spokesperson said on Monday it had been the “final offer”.
“The Royal College of Nursing was clear that talks will not be reopened if members reject the pay offer and we agree,” they said.
“We do think there is a fair offer on the table. We’re not looking to re-open it.
“This is a good and fair deal that is reasonable for them and for the taxpayer.”
Pat Cullen, the general secretary of the RCN, had recommended to her members that they back the deal. But it was rejected by a vote of 54% to 46%.
Following the vote, Cullen called on the government to make an improved offer.
Speaking in London on Monday morning, Sunak said renewed strike action in the NHS would make meeting his promise to cut waiting times “more challenging”.
The PM made the pledge as one of his five priorities at the start of the year, but the latest figures showed a record 7.22 million people were waiting to start routine hospital treatment at the end of February.