Junior doctors in England could stage a three-day walkout in March, a union has warned the government.
A ballot for the industrial action will open on Monday, the British Medical Association has confirmed.
Like recent strikes by nurses and ambulance crews, the dispute centres around pay amid rising inflation.
The current pay agreement for junior doctors ends in March 2023 – and the government says increasing pay in line with inflation is unaffordable.
Inflation – the rate prices rise at – is now 11.1%, the highest level for 40 years.
Below inflation pay rises add up to a 26.1% real-terms cut for junior doctors in England since 2008-09, the BMA says.
Basic pay for a new junior doctor is about £29,000 a year – though most will also receive overtime and unsocial-hours shift payments.
Junior doctors – those who have just graduated from medical school through to those with many years of experience on the front line – walked out of routine and emergency care in 2016.
Prime Minister Rishi Sunak has said he is working on “new tough laws” to protect people from strike disruption.
The government says it will consult on the adequate level of coverage for the emergency sectors, “recognising that disruption to blue-light services puts lives at immediate risk”.
For other sectors, including other health services, education, nuclear decommissioning, transport and border security, the government says it hopes to continue reaching voluntary agreements on minimum provision.
About 45,000 junior doctors will be balloted from Monday. If they strike, NHS trusts will have to arrange emergency cover to ensure patient safety.
Dr Vivek Trivedi and Dr Robert Laurenson, who co-chair the BMA junior doctors committee, said: “The prime minister says his door, and that of the health secretary, are ‘always open.’ This simply is not true.
“All our calls to meet, and letters to the health secretary and his immediate predecessors, have been ignored.
“When we are faced with such resolute ongoing silence despite all our attempts to start negotiations, then we are left with no choice but to act.
“Junior doctors are not worth a quarter less than they were 15 years ago nor do they deserve to be valued so little by their own government.”