St John has admitted an initiative to replace ambulances with single-crew vehicles has backfired, resulting in longer waits for some patients.
An Auckland paramedic - who the Herald on Sunday has agreed not to name - has expressed concerns over a shortage of frontline ambulances.
He said at least four double-crewed ambulances had been kept off the the road each day as part of a trial unofficially launched in November last year, while single-crewed cars were sent to call-outs.
The officer claimed the lack of ambulances and paramedics compromised patient safety and was worried it would cost lives. "Where people need CPR or defibrillation, those are your time-critical ones.
"You need to be there in a few minutes if you have any hope of getting them back. Personally, I've been the first ambulance turning up to those [critical jobs] 10 to 15 minutes after the call came in and, with that time, realistically the chances of them having any hope of survival is zilch."