Because of that St John set up an emergency operations centre in Auckland yesterday.
Ohs said it would help coordinate ambulance resources at a national level, ensuring resources were moved to where the need was the highest. Staff at the centre would also work with its health partners to ensure they could effectively manage demand on the ambulance service and respond immediately to critical patients.
Ohs said St John had already increased ambulance resourcing in the main centres and were supporting communications centres with additional capacity.
The centre would operate from 8.30am to 7.30pm daily to start with and focus on the pressures in emergency ambulance services and patient transfers in Auckland.
"To facilitate this we have declared a level two major incident, giving the emergency operations centre the mandate it needs to operate effectively."
Ohs said the demand meant those calling 111 may experience a delay before their call was answered and they may not be able to send an ambulance straight away if their condition was not immediately life-threatening.
He reminded people to call their GP or Healthline in the first instance if they were feeling unwell or needed health advice as well as consider other ways of getting to medical facilities for non-urgent conditions.
This comes as hospitals around the country report record levels of winter sickness among children.
The number of children seeking hospital care for the highly contagious respiratory syncytial virus has spiked over the past month seeing hospitals turn play rooms into extra space for beds, call in extra staff and bans on children visiting patients in hospitals.
ESR (Institute of Environmental Science and Research) data shows weekly visits to our six main hospitals for RSV had more than doubled in the past week, from 204 to 538 presentations. Only 34 cases were recorded between April to September last year.
In May, the Herald reported Auckland hospitals were overloaded with sick and injured patients being left in hospital corridors and ambulances queuing outside emergency departments because of skyrocketing demand.
Emergency responders were told to transport patients to "alternative facilities" such as community accident and medical centres or in less severe cases sending a paramedic to treat them at home.
In April, the Herald reported patients were waiting up to two hours for an ambulance, with St John confirming the "average" delay in transferring a patient into the care of emergency department personnel was between 30 to 45 minutes.