Tasmania has the most registered defibrillators per capita of any Australian state or territory, the island's ambulance boss says.

Ambulance Tasmania is developing an extensive community network of life-saving defibrillators that can be operated without training in a response to the ever-increasing demand on paramedic services.

Automated external defibrillators, or AEDs, come in a small pouch and offer voice prompts to deliver a reviving pulse to patients in cardiac arrest.

With more than 510 of the units registered, Tasmania has the most defibrillators per capita of any state or territory, said local ambulance boss Dominic Morgan.

"We now have one defibrillator per 1000 people in this state," he said on Tuesday.

"To put it in context, the next closest state is nearly two-and-a-half times behind us."

Tasmania's emergency service agencies have joined forces to add another 70 AEDs to the state network, with units based at offices or carried in some vehicles by police, the SES and fire service.

Voice prompts on the AEDs, which cost upwards of $2000 each, talk the operator through attaching pads to the patient's chest, standing clear and then commencing CPR.

Mr Morgan said an AED offered the best chance of survival from an out-of-hospital cardiac arrest.

When the ambulance service receives an emergency call seeking assistance for a suspected cardiac arrest, the nearest registered AED holder is alerted.

They will often reach the patient faster than an ambulance, although paramedics will still attend.

"It's a program where there are very few examples anywhere else in the world," Mr Morgan said, inviting anyone in Tasmania with an AED to register their device.

News of the growing defibrillator network comes as Ambulance Tasmania comes under growing pressure.

"In the last five years we've had a 23 per cent increase in ambulance demand in this state," Mr Morgan said, citing a variety of reasons.

"Most of the research points to the ageing population: Tasmania has an older population than the rest of the country.

"We also have some of the poorer health outcomes for more chronic conditions."