Unprecedented demand on the St John Ambulance service has forced it to set up an Emergency Operations Centre, something it would only normally do during a major emergency.
St John also issued a plea for people to only use the 111 service if it is an emergency.
Hospitals and healthcare systems across New Zealand are under pressure, partly due to an outbreak of RSV, or respiratory syncytial virus, among children.
St John had the busiest week it had ever seen last week according to Dan Ohs, St John deputy chief executive ambulance operations.
"While high demand over winter is not unusual, the current call volumes are well above what we would expect during this period due in part to the number of patients with viral respiratory illness, but also a general increase in other incidents," Ohs said
"Last week we received 1300 more 111 calls (11 per cent increase) and 700 more ambulance responses (7 per cent increase) than expected for this time of year."
Ohs said the demand was high among all parts of the population, but particularly with children, which was unusual.
In response, St John set up the Emergency Operations Centre (EOC) to coordinate ambulance resources at a national level, meaning resources can be moved to where the need is the highest.
Ambulance resourcing has been increased in the main centres along with additional resources for the communication centres.
Ohs said the EOC usually deployed during a major emergency such as an earthquake or during the Whakaari/White Island eruption.
"We have done it now not due to a single incident but because of the profound demand from the public which represents a significant concern within St John."
The increase is impacting the 111 service and the service’s ability to respond to emergencies. Callers are experiencing delays and Ohs asked the public to only dial 111 in an emergency.
"If people are feeling unwell, or need health advice, we are asking for them to call their regular health provider or Healthline and consider alternative methods of transport to medical facilities for non-urgent conditions.
"If it is an emergency, people should continue to dial 111 for an ambulance, being mindful that if their condition is not immediately life-threatening, there may be a significant delay in responding," Ohs said.