Up to June 30 this year, crews had 404 rescues, compared with 289 during the same period last year.
July saw 97 missions alone, including eight in just one day.
Canterbury West Coast Air Rescue Trust chief executive Christine Prince says the Covid-19 lockdown could account for some of the overall increase but it is an ongoing trend.
"By this time last year lockdown was over and the increase has continued strongly. As anticipated, mission numbers have increased this winter, with more people travelling locally and an increased risk of accident injuries and medical missions in the colder months."
Prince said the new helipad at Christchurch Hospital, which can take two choppers at a time, has been a gamechanger for the service with over 500 landings since it opened in November last year.
But she said as the need for the service increases, there's more work to do to fundraise for the widening gap.
More than $90,000 was raised at the Westpac Chopper Gala and Charity Auction in Christchurch last week.
"We are very grateful for the long-standing support of Westpac and all our fundraising community, many of whom are former patients," she says.
In trauma cases, such as road accidents and medical emergencies, getting emergency treatment to a patient within 60 minutes of an incident increases the patient's chance of making a full recovery by over 80 per cent, she said.
"In remote and hard-to-reach areas, the rescue helicopter service can mean the difference between life and death."
