St John is bracing for another spike in 111 calls this weekend as record-breaking demand for ambulances continues across the motu.

Citing extreme pressure from seasonal illness, St John declared a major incident response last Sunday and activated its Emergency Operations Centre for the first time since Covid-19 emerged.

St John said its major incident declaration would remain in place this weekend as it continued to manage sustained pressure across the ambulance service.

Ambulance operations director Doug Gallagher said the past week had continued to be very busy, with Thursday's volume of calls one of the five highest on record.

St John was managing the situation closely and ensuring it was fully staffed, he said.

"On Thursday 13 August, 2404 calls came into ambulance through 111, with demand continuing at the record-breaking levels experienced over recent weeks. We expect ambulance workload to remain high this weekend," Gallagher said.

"Despite the demand into ambulance [on Thursday], on average Hato Hone St John call handlers answered 94.1 percent of 111 calls within 15 seconds, and 7.4 percent of calls were managed through our Hear and Advise pathway, where patients received health advice without the need for an ambulance response."

Saturday, 8 August was St John's busiest day on record, receiving 2562 calls through 111, a 34 percent increase from a typical day.

"Maintaining the major incident response gives us a clear national structure for monitoring demand, ambulance availability and patient-safety risks, co-ordinating decisions and resources, and taking further action as conditions change. It also supports close coordination with Health New Zealand and hospital partners," Gallagher said.

Emergency ambulance help remained available, and people should call 111 immediately when someone is seriously ill or injured, or there is an immediate threat to life, he said.

"For non-emergency health concerns, people are encouraged to seek advice early and check which services are available locally.

"These options may include an online GP, a pharmacist, an urgent care clinic or a free call to Healthline on 0800 611 116. This is available 24/7 and there is a callback option available if you would like Healthline to call you. Visit healthy.org.nz to find out more.

"We are reminding the public again to please be kind and respect our ambulance staff, whether you're on the phone to them, or they're treating you in person. They are working incredibly hard under immense pressure."