NHS staff are quitting because they are stressed and burned out from heavy workloads, having too little time with patients and suffering bullying and harassment at work, an official report has said.

The exodus is deepening the service’s workforce crisis in England, making it harder for patients to see a GP or hospital specialist and forcing the NHS to rely on expensive agency staff.

Disillusioned doctors and nurses are leaving the health service at all stages of their careers because they find working in it too much, the new workforce strategy drawn up by NHS leaders warns.

The NHS must do more to tackle the high dropout rate by making “a new offer” to its 1.3 million personnel that is intended to make their working lives easier by providing more flexible hours, the ability to work from home and better mental health support, the Interim NHS People Plan says.

“Healthcare jobs have become increasingly demanding as the NHS has struggled to recruit and retain people, and existing staff work harder to maintain standards of care,” according to the 74-page document.

“These gaps in our workforce make it difficult to fill medical and nursing rotas and provide enough general practice or outpatient appointments, as well as increasing financial pressures on the system as gaps are filled with higher cost temporary staff.

“The culture of the NHS is being negatively impacted by the fact that our people are overstretched,” adds the report. It warns that the service will keep losing staff unless it changes how it treats them and becomes England’s best, not just biggest, employer.

The pressures of working in the NHS mean sickness absence is 2.3% higher than in the rest of the economy and contribute to one in 11 staff quitting every year, it acknowledges.

The plan was drawn up by Dido Harding, the Conservative peer who chairs NHS Improvement, a health service regulator, alongside NHS chiefs, trade unions and workforce experts. Originally due in 2017, it has assumed major importance within the NHS as the health service looks for ways to tackle its twin crises of recruitment and retention, which have left it short of more than 100,000 staff.

The plan sets out “urgent action” to improve the situation, including:

The recruitment of more overseas nurses, although a target of 5,000 a year from now until 2024 has been dropped.

Similarly, a greater reliance on doctors from abroad.

A review of NHS pension taxation rules which have prompted growing numbers of doctors to take on less work or retire early.

A new campaign, in tandem with Mumsnet, to encourage more nurses to return to the NHS.

The 40,000 vacancies for nurses is the most pressing of the NHS’s many “significant staff shortages across the country”. The report sets out an ambition to increase the number of homegrown nurses and notes that the then chancellor, George Osborne’s decision in 2016 to abolish bursaries and maintenance grants for student nurses and midwives led to a 31% fall in applications for degrees in those subjects. However, it does not recommend that either form of financial support should be reinstated.

Harding’s plan makes clear there will be no money to use to tackle understaffing until after the next spending review, which NHS leaders hope will bring extra cash to address the problem. A final and fully costed People Plan will be published “later this year”.

“The plan acknowledges the damage caused by the government’s education reforms, including the abolition of student bursaries, yet offers little action to address this. This needs the government to act by offering more financial support to student nurses,” said Suzie Bailey, director of leadership and organisational development at the King’s Fund thinktank.

Hospitals and other NHS care providers will offer staff the chance to work much more flexibly in future to reduce the rising number quitting because they feel they cannot have a decent work-life balance.

The People Plan says: “We will significantly increase flexible working through a combination of technology and a change in people practices, to give people greater choice over their working patterns, help them achieve a better work-life balance, and help the NHS remain an attractive career choice.

“We will need to advertise more roles as flexible (for example, less than full-time, term-time only, job shares) and, where possible, enable home working to bring our employment offer into line with other sectors.”

Harding said: “We need to change the way people work in the NHS to recognise the changing needs of patients and to create a modern, caring and exciting workplace that should be the best place to work in England.”

Experts gave the plan a cautious welcome. “This plan hits the right note in calling for a better, kinder culture in the NHS. But a good culture won’t make much headway when staff are seeing unsafe shortages every day,” said Nigel Edwards, chief executive at the Nuffield Trust thinktank.

Ministers needed to rethink planned post-Brexit immigration rules which, if the proposed £30,000 minimum salary entry condition were not waived, would deprive the NHS of many overseas recruits and “put the entire plan in jeopardy”, added Edwards.

Matt Hancock, the health secretary and a Conservative leadership contender, said on Monday that if he became prime minister he would give doctors from anywhere in the world an “unrestricted right to work in our NHS and live in our country”.