The number of rescues, vehicle crashes and medical incidents attended by fire crews in Otago has increased by nearly 40% since 2014.
Figures released by Fenz under the Official Information Act show the rise in medical and crash calls began in 2015, following an agreement with St John in December the previous year for Fenz to respond to more medical callouts.
The number of such calls rose steadily each year since the agreement, from 1086 in 2014 to 1501 last year.
In the year to the end of July, Otago crews attended 975 medical calls or crashes, meaning 2018 is set to be another record year for medical and crash calls.
Most of the biggest increases were in rural areas, small towns along state highways and popular tourist areas, overseen by volunteer brigades.
The Waikouaiti Volunteer Fire Brigade went from three medical and crash calls in 2010 to 24 in 2017.
Wanaka attended 47 last year compared with 13 in 2010, while Balclutha jumped from 18 to 59 over the same period.
The busiest station for such calls last year was Lookout Point in Dunedin (manned by paid firefighters), with 148, followed closely by the Port Chalmers volunteer brigade's 121.
Waitati Chief Fire Officer Jeff Burrow's volunteer crews attended 31 medical events or crashes last year, up from seven in 2010.
The role of volunteer firefighters had changed hugely, he said.
''It's a whole lot different than it used to be.
''When I first signed up, we just fought fires.''
Mr Burrow said most of the calls were medical events rather than crashes, and many of his crew members were now trained as medical first responders.
Fenz region five manager David Guard said the 2014 agreement with St John was signed because in some parts of the country the nearest fire station was much closer than the nearest ambulance.
''The change has increased the number of callouts attended by our crews, particularly our volunteers, but it has also saved lives.
''Resuscitation rates have increased from 8 to 12%.''
Mr Guard said all staff who respond to medical events received training from St John, and free psychological support and counselling was available for firefighters and their immediate families.
A new mental health programme was also under way, he said.
''Nationally we have just begun rolling out psychological health and wellbeing workshops that will equip those attending to not only better manage their own health and wellbeing but also to better support the people around them.''
