Myocarditis is an inflammation of the heart muscle wall which is often caused by a viral infection. It is a known but rare side effect of the Pfizer vaccine.
Weeks before the individual's death, MoH said, they had received a dose of the Pfizer COVID-19 vaccine.
"The Board considers that the development of myocarditis was possibly due to vaccination with the Pfizer COVID-19 vaccine. It's important to note this case is with the coroner who is still investigating the cause of death.
"This is a tragic circumstance, and the Board expresses their sympathy to the individual's whānau and friends."
While the majority of cases are minor, according to MedSafe, there have been 156 deaths reported with possible links to the vaccine.
Of those, only two have previously been considered linked to the vaccination, according to MedSafe.
Eighty-nine of these deaths are unlikely to be related to the Covid-19 vaccine and 14 cases are still under investigation.
Fifty-one could not be assessed due to insufficient information, according to MedSafe.
All three cases of deaths which have been considered linked to the vaccine are currently with coroners to determine the cause of death.
According to MedSafe, the observed number of deaths reported after vaccination is less than the expected number of natural deaths.
There have been no deaths reported for the AstraZeneca vaccine.