Professor Gillian Whalley, of Unitec, has been awarded a $200,000 grant from the Health Research Council for the study.
She said there was strong evidence heart size was determined by ethnicity.
"I started taking an interest in this about 10 years ago when I noticed that many of our Maori and Pacific patients had quite large hearts but were otherwise healthy.
"They do have slightly bigger hearts, but their muscle mass is quite a lot bigger for a given height, so if you took a European and a Maori or Pacific Island person of the same height, the Maori or Pacific Island person may have a lot more muscle and a correspondingly bigger heart."
But there was no accurate data to confirm the appropriate healthy heart size for Maori and Pasifika people. This meant that for 20 per cent of New Zealand's population, a diagnosis of heart disease was based on incomplete information.
"Flexibility is introduced in a random way into those normal ranges, and that's where it gets risky," Professor Whalley told the Herald.
"It's hasn't been quantified before - nobody has put a line in the sand and said this is what you should expect in a Maori and Pasifika person - and that won't do.
"How did we end up in this situation? We've been doing ultrasound on hearts since the 70s and we're now only just realising that we're not doing the basics very well.
"We're doing it okay, but we're not doing it really well."
She has been working since 2010 with University of Auckland researchers on a study called Echo-Normal, which gathered data from 23,000 people from 32 studies from every continent and proved the correlation between heart size and ethnicity.
Professor Whalley said Echo-Normal, funded by the Heart Foundation of New Zealand, showed most European people shared a similar range for heart size, but the limits for heart size were higher in African Americans and lower in different Asian groups.
These size differences were "of a magnitude that would make a difference to whether you get treatment for a heart condition or not".
To establish a range of normal heart size for Pacific Islanders and Maori, she will draw on data from hundreds of healthy Maori and Pacific Islanders.
The cardiology community, which has welcomed the study, would use the findings to create guidelines.
"Health professionals know there's a problem, they just don't know how to solve it. This project will provide the data to be able to solve it."
How to take part
Professor Gillian Whalley is seeking 900 healthy participants with no diabetes or known heart conditions for her study into the link between heart size and ethnicity.
These would include 300 Maori, 300 Samoan and 300 European participants between the ages of 18 and 50, with an even split between men and women in each of the groups. Would-be candidates can email Professor Whalley at gwhalley@unitec.ac.nz
Kiwi cardiac project a medical first
A team of New Zealand researchers will create the world's first "statistical atlas" of the anatomy of coronary arteries - something hoped to improve the design of coronary stents.
Blockages in the coronary arteries can cause reduced blood supply to the heart, heart attack and sudden death.
Each year, more than two million stents - small metal inserts that hold arteries open to treat heart attacks and angina - are used worldwide.
But Dr Pau Medrano-Gracia, a postdoctoral research fellow at the University of Auckland, said there was a limited range of standard stents for a wide variation in the size and shape of coronary arteries.
"We want to define the average coronary anatomy of the general population, but as everyone has arteries of different size and shape, we have needed to use advanced statistical modelling techniques to generate the average models."
Dr Medrano-Gracia will lead a team that has been granted $200,000 from the Green Lane Research Educational Fund Board to create a detailed statistical atlas of coronary arteries.
Ultimately, this will also allow accurate 3D replicas of a patient's coronary arteries to be made from plastic or silicon using high-resolution 3D printing.
