There are calls for defibrillators to be made compulsory at public buildings and workplaces in Victoria.
Figures show 30,000 Australians suffer a sudden cardiac arrest outside hospitals each year.
Werribee South and Hoppers Crossing are among the top Victorian regions for people to suffer a cardiac arrest.
St John Ambulance data shows 285 people suffered a cardiac arrest outside hospital in Werribee South in the five years to 2022.
In Hoppers Crossing, that number was 226.
St John Ambulance wants Victoria to follow South Australia’s lead in making the defibrillators mandatory.
The Victorian government says there were 7,000 machines registered across the state.