Stacey Waldron, of Alexandra, says she is saddened and frustrated to see Wanaka's two permanent ambulance officers having to be on call some nights to cover for a lack of available volunteers.
She contacted the Otago Daily Times after reading in Saturday's paper about the shortage of volunteers in the town.
She believes two more permanent staff should be employed in Wanaka.
"I just want to see a change so no other family has to go through the pain, heartache and court proceedings we experienced when we lost our Nana."
Mrs Waldron's grandmother, Anne Sharp, died in March 2003 when her car was hit by an ambulance on the wrong side of the road near Allanton, south of Dunedin.
After a defended district court hearing, the ambulance driver, Carol Ann Forrest, of Balclutha, was found guilty of careless driving causing death.
Judge John Macdonald said he believed the ambulance driver had probably fallen asleep at the wheel as the result of long hours working as a nurse and as a St John ambulance volunteer.
Mrs Waldron said she had no desire to be critical of ambulance staff but believed "the hierarcy" had failed to learn the lessons of the past.
"Once again, our St John ambulance volunteers and paid staff are being put under enormous pressure by hierarchy and are working too many long shifts."
Wanaka operation team manager for St John, Don McMillan, outlined to the Otago Daily Times last week the "short term fix" he and paramedic Rod Walker had to cover volunteer unavailability at night.
On Friday and Saturday nights, Mr Walker was on call.
Volunteers were available for Sunday night.
Mr McMillan said it had been a fairly quiet weekend, with just one call out each night.
Sufficient volunteers are available for this weekend.
