A report on Niue's Lord Liverpool Hospital has alleged that patients have been misdiagnosed or received the wrong treatment on at least five occasions.
A former medical officer at the hospital, Dr Mary-Jane Vega, says in one case an elderly patient was due to have an arm amputated following a burn, but instead the patient was flown to New Zealand.
Doctors there concluded the amputation was unnecessary.
Dr Vega's report was written for the government, but has been leaked to local media.
She said she drew up the document in an effort to improve medical practices on Niue, which she claimed were way behind current performance levels.
The death of MP Hunukitama Hunuki earlier this year is already subject to a police report and is due to go before the Coroner next year.