Many people with symptoms of a heart attack are not seeking medical help for days, the Heart Foundation says.
The foundation is launching its largest awareness campaign so far today to challenge a "she'll be right attitude" to the symptoms of a heart attack.
It says Kiwis take too long to seek medical attention when they or someone nearby presents with the symptoms of a heart attack.
A survey of 1422 people in May found people do this because of a non-urgent attitude, concerns about the cost of an ambulance and medical care, and a fatalistic view that this was meant to happen.
People experiencing or witnessing a heart attack often feel like they need permission to call for an ambulance, the foundation says.
"It's time for Kiwis to start taking their heart health seriously," foundation medical director Dr Gerry Devlin said.
"Heart disease is New Zealand's biggest killer."
The research also revealed that communities most likely to delay calling for urgent medical care were those in lower socio-economic areas.
Dr Devlin said many people recognised symptoms such as chest discomfort but not the less obvious signs of an attack, which can include pain in the jaw, shoulders or back, or excessive sweating, shortness of breath and nausea.
The campaign includes a television commercial, radio ad, online video, posters, flyers and letterbox drops.
It is funded by the foundation, the Ministry of Health, and AstraZeneca, a biopharmaceutical company.