Half of the junior doctors in the NHS are expected to strike from this morning following the bank holiday weekend bringing fears to patient safety.

People can expect a significant impact to health services in Kent and Medway during industrial action planned by junior doctors following a worsening dispute over pay.

The walkouts are set to last from 7am today until 7am Saturday, April 15 making it the longest industrial action, which has seen nurses, ambulance crews and other health workers take action since last year.

An estimated 350,000 appointments, including operations, will be cancelled as a result of the walkout by members of the British Medical Association (BMA).

Managers have said patient care is “on a knife edge” because of the strike, while NHS Confederation chief executive Matthew Taylor saying the number of appointments cancelled, previously suggested to be 250,000, was likely to rise by another 100,000.

The strikes centre around a pay row between the BMA and government, with the union claiming junior doctors in England have seen a 26% real-terms pay cut since 2008/09 because pay rises have been below inflation.

The union has asked for a full pay restoration that the government said would amount to a 35% pay rise – which ministers have said is unaffordable.

BMA officials said the pay issue is making it harder to recruit and retain junior doctors, with members previously walking out for three days in March.

National medical director of NHS England Professor Sir Stephen Powis said on Sunday the strikes will put “immense pressures” on staff and services.

NHS England said staff will be asked to prioritise emergency and urgent care over some routine appointments and procedures to ensure safe care for those in life-threatening situations.

The health body said appointments and operations will only be cancelled “where unavoidable” and patients will be offered alternative dates as soon as possible.

Health and Social Care Secretary Steve Barclay said: “It is extremely disappointing the BMA has called strike action for four consecutive days.

"Not only will the walkouts risk patient safety, but they have also been timed to maximise disruption after the Easter break," he said.

"I hoped to begin formal pay negotiations with the BMA last month but its demand for a 35% pay rise is unreasonable – it would result in some junior doctors receiving a pay rise of over £20,000.

"If the BMA is willing to move significantly from this position and cancel strikes we can resume confidential talks and find a way forward, as we have done with other unions."

NHS Kent and Medway’s chief medical officer Kate Langford said: "We are working closely with our partners to make sure patients can access the care they need, in a safe environment, during industrial action by junior doctors.

"We anticipate and are planning for the action to have significant impact on services provided across all areas of the NHS, including our hospitals, accident and emergency departments, primary care (GP practices) and mental health services.

"Regardless of any strike action taking place, it is important patients who need urgent medical care continue to come forward as normal, especially in emergency and life-threatening cases - when someone is seriously ill or injured, or their life is at risk."

Patients have been advised to go to any planned appointment as normal unless they hear otherwise. If industrial action means their appointment has to be cancelled, their hospital, GP or other provider will directly contact them to make alternative arrangements.

NHS bosses are also asking that patients only go to emergency departments if they are facing life threatening injury or illness.

"Care is available across Kent and Medway through other NHS services, including urgent treatment centres and pharmacies. Please use these for less urgent health needs," the NHS website says.