Waikato Hospital was at capacity today and warning people to only go to its Emergency Department if it was a "real emergency".
Elective surgeries other than cancer or other emergency type surgeries were also cancelled today as the hospital dealt with the overflow of patients.
Patients slept on beds in the corridors of the ED on Monday night as there were no beds left in the wards.
The Waikato DHB posted a video on its Facebook page at Tuesday lunchtime telling patients to check with their GPs or call Healthline first and only go to the emergency department it was a "real emergency" or be prepared for a long wait.
"Today our Emergency Department at Waikato Hospital is in overload and Waikato Hospital is full," the message said.
Waikato Hospital Services executive director Brett Paradine said by Tuesday afternoon the ED was back to running at normal capacities and all patients had beds. However its message that the ED should only be used for emergencies still stood.
Paradine said the overload was due to a higher number of presentations than normal in the morning and fewer discharges than expected. Although patients slept in corridors they were "all cared for".
The hospital has been at capacity several times this winter and Paradine put it down to an increase in a whole range of presentations, especially respiratory illness.
"The number of people coming to Waikato Hospital has increased 20 per cent over the last five years. Patients are also often sicker and consequently spending longer in the hospital, which is putting more pressure on hospital beds," Paradine said.
The first new ward in five years, aimed at geriatric and rehab patients, opened last week and it was hoped the additional 27 beds would ease the pressure.
Waikato DHB had also enhanced theatre usage improved patient flow to deal with the influx.
Waikato Hospital is not the only hospital feeling the pressure. Last month Middlemore Hospital put up a sign on the door of its ED telling patients the hospital was full and to expect delays of up to eight hours to be seen in the emergency department.
North Shore, Waitakere, Auckland City, Palmerston North and Hawke's Bay Hospitals have also been at capacity at least once this winter.
Association of Salaried Medical Specialists executive director Ian Powell said an overflow of patients meant senior doctors and other health professionals would be severely overworked and under considerable pressure.
"They will be working in a very difficult environment that is also stressful."
Powell said the larger hospitals appeared to be increasingly reaching capacity and while the Waikato DHB had opened a new ward it would only cater for a sub-set of the patients needing care.
Labour spokesman for Health David Clark said hospitals were reaching capacity too often. "Obviously when that happens if there's a major disaster or epidemic the hospital won't have any capacity to cope."
Hospitals were also often under staffed which meant patients weren't being processed as quickly, he said. Clark also believed cheaper GP visits would encourage people to get treated early and prevent them even having to visit the ED.
NZ First Hamilton East candidate Pita Paraone said it was scary that the hospital was full as it should never get to that point.
Paraone knew of one elderly patient who spent 24 hours in ED before being admitted to a ward.
"As the demand for health services grow, the insufficiency of all that (being told to go to the GP or call Healthline) is heightened and I think the New Zealand public deserves better."