The ambulance service Hato Hone St John is hoping to equip 10,000 people with the skills to intervene during a cardiac arrest - or heart attack.

It has started an initiative called "Shocktober", aimed at teaching people the steps to take when faced with such an event, such as chest compression and using a defibrillator.

Free public training events will be held throughout the country as part of the initiative.

The service's head of community education, Jacci Tatnell, said New Zealand's heart attack statistics were shocking, but timely interventions could increase survival rates.

"Every year, more than 2000 people in New Zealand are treated for cardiac arrests and only 25 percent survive to hospital, and then 11 survive out of hospital," she said.

"The survival rate of a cardiac arrest is really low and it's really proven that effective CPR, ringing an ambulance and using AEDs (automated external defibrillators) makes a huge difference to a person's

chance of surviving."

Cardiac arrest remains one of the leading causes of death in Aotearoa.