A letter from NSW Ambulance Service chief executive Greg Rochford obtained by The Herald refers to plans for volunteers to stand in as drivers to cut the number of single-crew ambulance shifts.

"The Ambulance Service has been investing in alternate models of care and one model is designed to strengthen and foster the long traditions of partnership between communities and volunteers and ambulance," Mr Rochford wrote.

Merriwa Progress Association president Kim Fenley said it was unacceptable for small towns to be serviced on some nights by one-officer ambulances, but volunteer paramedics were not the answer.

"It's a substandard solution, and it's their way of trying to plug the holes they should have filled if they did their job at headquarters," Mr Fenley said.

"Out here we have major accidents, some with four or five [people] involved, and those lives are going to be in the hands of a single trained officer."

Other towns served by just one paramedic on some nights include Bulahdelah, Stroud, Gloucester and Murrurundi.

More than a third of the population of each community is older than 55, nearly 10 per cent more than the state average.

Merriwa has 341 people older than 55 out of a population of 945, and Mr Fenley said many older residents feared having heart attacks and being treated by understrength ambulance crews.

The Health Services Union's Outer Hunter sub-branch voted this month to reject the Ambulance Service proposal.

The NSW Ambulance Service and state Health Minister Carmel Tebbutt declined to comment last night.