But there were many times the committee doubted it would reach the milestone.
Finding volunteers for the service, which is stationed in Kurow has always proved difficult.
Last year's census found the township's population was 312.
For Kurow-based volunteers, being part of St John requires a constant juggling act between work, family, and providing a valuable service for their community.
At present, there are 16 operational staff and a committee of eight members, some of whom are also operational volunteers.
But at times, they have struggled with as few as four volunteers.
The St John Waitaki area committee was established in 1964 by six Kurow people. One of the founding members, Eileen Gordon, said her late husband ran a taxi service at the time.
''We always seemed to be rushing someone away to the hospital [in the taxi] and then we decided there were too many sick people around and we needed to do something,'' Mrs Gordon said.
''We were always busy because the dams were busy; that's where it all started.''
The need really hit home after the death of a friend while she was being transported by car from Kurow to Oamaru Hospital.
''I'm sure if we had an ambulance here we could've saved her,'' Mrs Gordon said.
''That put me into perspective - we've got to do something.''
It took much hard work, and the Kurow group was
given some ''marvellous'' assistance by Oamaru St John.
It took about six years to raise enough money to have
an ambulance permanently based in Kurow. The vehicle was initially housed in a garage at the back of the Kurow Motor Company.
Their first ambulance was a ''rattly old thing'' and the back compartment was shut off from the driver. If volunteers wanted to communicate with the driver, they had to ''hammer like hell on the window'', Mrs Gordon said.
''On a frosty night, ... we always took hotties for the patients, it was so cold, but it was a wonderful service and we needed it badly,'' she said.
Another massive fundraising effort by the community resulted in the service getting its own building, with an ambulance bay and office space, which was opened in 1976.
Mrs Gordon was involved in the St John Waitaki Area Committee for 44 years.
Originally from Palmerston, she moved to Kurow when she was 22.
''I got married, and thought I wouldn't last a week [in Kurow] and I'm still here,'' she said.
Being a St John volunteer was a ''wonderful experience'', offering a variety of life skills, she said.
The St John Waitaki area committee covers a huge area, from Duntroon and the Danseys Pass area, up the Hakataramea Valley and Cattle Creek, and inland as far as Lindis Pass - and sometimes to Mt Cook and Waimate.
It deals with an average of about 12 call-outs a month and its drivers cover about 1000km.
A dinner will be held for all current and past volunteers and committee members on Saturday, November 15 to celebrate 50 years caring for the community.
