Calls to the St John 111 communications centre in Christchurch and Auckland increased last year, with centres answering 46,000 more calls than in 2018.
Ninety-five percent of calls are answered within 15 seconds.
Call-outs also increased nationally by four per cent in 2019, to 440,000. Twenty-thousand of those people were having some form of mental health crisis.
St John operations director Norma Lane said this statistic was in line with global and national trends on mental health.
People aged 70-79 had the largest increase of this group and callouts from men now make up almost half of all mental health related calls, up from 39 percent in 2018.
The top five reasons an ambulance was called were referrals by GPs, falls, breathing problems, chest pain and people unconscious or passing out.
Lane said response target times were still being met for the most serious cases, but higher workload, traffic congestion and more time-consuming cases were all having an effect.
Not all calls into the 111 emergency call centre require an ambulance, and St John clinicians help determine what care is best.
That could be self-care, referral to a GP, referral to a private accident and medical centre or an alternative vehicle to treat the patient at home, Lane said.
"A lot of work is being done to take pressure off the wider health system and in 2019, 170,000 incidents resulted in people being treated at home, given advice over the phone or directed to more appropriate care by our clinicians, rather than presenting at hospital emergency departments."
St John is in year three of a four-year programme to fully crew all ambulances.
"Ambulances are now fully crewed 97 percent of the time and we are on track for all ambulances being double crewed in 2021," Lane said.
