Hospitals are already overrun on the first day of winter with emergency departments dealing with a massive influx of sick patients.
It comes as a mix of COVID-19, winter bugs and staffing shortages puts immense pressure on the healthcare system with an expert warning in the worst-case scenario "hospitals won't be able to cope".
Association of Salaried Medical Professionals Executive Director Sarah Dalton told AM hospitals around the country are under massive amounts of stress.
"This is only the first official day of winter. So normally most years we talk about a winter surge, this year it is starting to look more like a winter tsunami and it is incredibly concerning," Dalton told AM's Melissa Chan-Green on Wednesday.
She also issued a stark warning that in the worst-case scenario hospitals won't be able to cope and patients might be left waiting in ambulances because there are no beds.
"What we are seeing is people are having to wait for very long times to be seen and it's very cramped and it's not ideal when we still have a lot of infectious diseases.
"We've got projections that suggest with the borders reopening it's not just COVID, there is a lot of infectious disease around this winter so there is a huge risk and… if we hit the worst projections our hospitals won't be able to cope."
Dalton said hospitals need to be really upfront about their capacity and wait times and people should only go to the emergency department if they are really sick.
"The message coming out from the hospital is if you feel a little unwell, try to see a GP or ring Healthline, rather than waiting to get really, really unwell. Obviously, if you're very sick you need to go to a hospital."
It comes as several hospitals around the country have been forced to delay surgeries or even ask patients not to show up unless they're extremely unwell due to staffing issues.
On Tuesday Christchurch Hospital was forced to cancel surgeries because they didn't have enough staff or beds.
Capacity at the hospital is currently sitting at 112 percent.
