Volunteer numbers for the Palmerston ambulance station have dropped to nine, but should sit at 25.
Tania Bungard said the station was three years old and still in a growing phase, but volunteers were needed so the town could keep its ambulance service available 24 hours a day.
"We're fully committed to keeping our service 24/7, but it's getting to the point where we may need to take our ambulance off the road.
"That means calls will go to Dunedin or Oamaru, but if they're busy your wait time may take up to an hour.''
When the station was opening, a block training course was run for about 14 volunteers, but demands on peoples' time altered, people left the service, leaving the station's numbers at a static point, she said.
A lot of her volunteer staff were doing four to six 12-hour shifts a week to keep the town and surrounding area serviced.
"It's a lot of hours for our volunteers.''
Mrs Bungard said over the past year from July 1, 2015, to June 30, 2016, Palmerston St John attended 522 jobs including medical assists and car crashes.
She said it was clear to many in the community how hard the ambulance unit worked and she thought some people might be deterred from joining due to the workload.
However, that could change if more volunteers enlisted and the load could be shared.
She said Palmerston's ambulance unit had camaraderie and all members were committed to serving the area and its needs.
"I love it.
"I enjoy working with my team here.
"We've got a great bunch.''
To find out more about volunteering at Palmerston St John, email: tania.bungard@ stjohn.org.nz.
