Hospitals are creating thousands of extra beds, hiring more staff and getting doctors to work longer shifts in a frantic effort to avoid the NHS being crippled by major problems this winter.

Fears that the service may face its toughest ever winter have forced NHS trusts to use beds in nursing homes, reopen disused wards and build new ones to boost their capacity. At the same time trusts are recruiting nurses from abroad to tackle staff shortages so they can cope with the expected impact of flu, norovirus and bad weather.

Dame Barbara Hakin, the NHS's deputy chief executive, said the service had "pulled out all the stops" and taken unprecedented steps to prepare for winter in a bid to avert a crisis. Plans have been laid for several thousand more beds being available during the next few months, GPs to offer more appointments and ambulance services to have extra staff, Hakin added.

One trust has even obtained a prefabricated building to use as an overspill ward if it comes under particular pressure.

The moves come amid mounting anxiety in government, the leadership of the NHS and hospital bosses that the service could be overwhelmed by the demand for care as winter bites.

Chris Hopson, chief executive of the Foundation Trust Network, which represents almost all England's acute hospitals, told the Guardian hospitals are under "unrelenting pressure" for so much of the year now that some had to activate winter strategies up to two months ago, ahead of schedule. "Many trusts have had their winter plans running since September to ensure they cope with the level of demand," he said.

As part of its plans, County Durham and Darlington NHS foundation trust has created 25 extra beds at the University hospital of North Durham by reopening a ward, and another 25 at the Darlington Memorial hospital by putting extra beds into existing wards.

It has also hired 39 more nurses to staff the two hospitals' A&E units, created an extra intensive care bed and arranged for local nursing homes to look after 10 patients who need rehabilitation rather than treatment in a bid to ease demand for beds in its hospitals.

Professor Chris Gray, the trust's medical director, said the 50 extra beds were needed to meet demand from the sheer number of patients arriving as emergencies who need to be admitted, and to ensure elective operations and urgent cancer care were not affected by such pressures. Extra beds created last winter at the University hospital of North Durham as a temporary measure have remained open ever since because of what Gray said were now "all-year-round pressures". A rise in emergency patients led to "particular pressures" on the hospital in September and October, he said.

Under its winter plan, Airedale general hospital in Keighley, west Yorkshire, has moved to create 55 more beds. Extra nurses to cover the 24 new medical beds will cost £806,000. It is reorganising which wards handle what types of patients in order to avoid patients admitted as medical emergencies having to "sleep out" – spend the night in wards that are unsuited to caring for their needs, notably those full of surgical patients – or cancel operations due to a lack of beds. It is spending a further £383,395 on extra nurses for its specially designated 30-bed "winter ward". It is also trying to ease pressure on beds by cutting emergency admissions by 4%, reducing the average length of stay from 5.8 to 5.3 days and discharging more patients earlier in the day.

In Leeds, St James's hospital and Leeds General Infirmary are getting an extra 65 beds, with 14 more on standby – though plans for even more extra capacity had to be shelved due an inability to recruit sufficient nurses – while doctors will be working longer hours. Derriford hospital in Plymouth is adding 50 beds and creating a short-stay unit for patients staying up to 48 hours.

The trust that runs Cheltenham general hospital and Gloucester Royal hospital has been recruiting some of its extra 35 nurses from Portugal and plans to open two extra medical wards at Gloucester Royal. "In the middle of winter we can see an extra ward of patients coming in on any day", said Frank Harsent, its chief executive, who wants to avoid a rerun of last year's "difficult" winter.

Although hospitals have been given almost £400m in extra funding to tide them over this winter some have used their reserve or surplus to fund measures to meet winter's extra demand, said Hopson. "Everything that can be done for this winter is being attempted on the frontline. Trusts have been putting more money into meeting this demand by recruiting more staff, buying extra equipment, building and extending wards and emergency units and improving links and working arrangements between community, mental health, ambulance and hospital teams."

Some hospitals, such as University College hospital London, are building completely new and bigger A&E units to cope with the general trend for more attendances and more admissions.

Basildon and Thurrock University hospitals NHS foundation trust has been building a new 28-bed ward as part of its plan to increase capacity by 67 beds, earmarked £1.8m to fund 200 extra nurses across its hospitals and also obtained a prefabricated building to provide extra capacity.

Research by NHS England shows that while fewer people actually attend A&E in winter than in summer, they are much likelier to need to be admitted. That can lead to hospitals becoming full, operations being cancelled because the beds for those patients are needed, patients who have been treated in A&E having to wait on trolleys for hours before being given a bed and new arrivals having to wait in ambulances outside – a condition Professor Keith Willett, NHS England's national clinical director for acute care, calls "congestive hospital failure".

While low levels of flu and norovirus so far this winter, and the absence of very bad weather, mean hospitals have generally not yet been sorely tested, they are bracing themselves for the months ahead. The medical director of one trust told the Health Service Journal recently that despite the extra £400m, "It's all going to go completely pear-shaped and they know it. It's entirely predictable."

Hakin, who is in charge of NHS England's winter preparations, admitted hospitals are already busy. But, she added: "It is absolutely right to be totally alive to the risks during winter but it's also important not to call a crisis before it has happened. We are right at the start of winter and we are not complacent. But we can be heartened that at the moment we are seeing and treating patients quickly in our A&E departments with those not admitted generally seen and treated in under two hours.

"Everyone is working really hard to make sure we manage this winter just as well as we have done in the past. The challenges are significant but the effort we are putting in to meet those challenges has never been greater and our planning and co-ordination has never been as meticulous nor as advanced at this stage of the year as it is now."