Sickness bugs, virulent flu and accidents due to the cold snap have increased pressure on GP surgeries and left parts of the health service "at breaking point", it has been claimed.
Extra GPs have been called in to cover casualty units after hospitals were overrun last month as nearly 100,000 more patients attended A&E units during December than the year before, according to figures from the Nursing Times.
Wards were forced to close and patients moved to nearby hospitals after 1.5 million patients sought emergency care throughout the country – 92,601 more than in 2007 and an increase of almost 7%.
Other measures include the drafting in of social services staff to fast-track discharges and the cancellation of routine operations.
Patients with flu-like symptoms have also been asked to stay away from hospitals and only call for ambulances when absolutely necessary.
Alan Dobson, from the Royal College of Nursing, said: "The pressure is going to take its toll. Where you have a 7% increase and that continues, departments are going to be at breaking point. Staff become sick and that compounds the problem. It is an issue across the country."
Mr Dobson said the problem could get worse if temperatures dip to previous lows.