The Pandemic Influenza Mortality and Morbidity Review Group revealed that nationally, 49 people died of swine flu, not 35 as previously thought. Otago's confirmed deaths included one person who died while in the Cook Islands on holiday.
Chairwoman of the group, Prof Cynthia Farquhar, said the additional deaths were identified through access to data such as births, deaths and marriages, laboratory results and clinical notes.
"I would also like to acknowledge the losses suffered by many New Zealand families ... last year, especially given that so many of those who died were younger than usually occurs with seasonal influenza", Prof Farquhar said.
Otago and Southland Medical Officer of Health Dr Derek Bell told the Otago Daily Times a fourth Otago death could yet be confirmed.
Of the national total, 26 deaths were women and 23 men. Sixteen deaths were at home and 33 in hospital.
A high proportion - 86% - had other conditions underlying their influenza, most commonly respiratory disease, obesity, and substance abuse. There was also a link with social deprivation.
Three women died after giving birth, following influenza in the third trimester of pregnancy.
Of the 16 who died at home or in the community, four had seen their GP after onset of symptoms, including one who had been discharged from hospital, and the Otago tourist in the Cook Islands.
"It was also concerning that 16 patients died at home or in the community, only a few of whom had sought the assistance of the health services.
"There is a need for further work on public health messages, so that they convey the range of influenza presentations."
Two patients admitted for other reasons contracted swine flu while in hospital.
Only 41% of the patients who died presented with classical flu symptoms, and 37% had no fever or flu symptoms.
More patients were prescribed antibiotics than antiviral medicine. The report said this may reflect the fact antibiotics were not restricted in primary care, and that practitioners were more accustomed to prescribing them.
The Ministry of Health had improved access to antivirals, like Tamiflu, making it free of charge with a prescription.
Otago had an extremely low rate of intensive care unit admissions, just two, compared with three in Southland and one transfer or re-admission in Southland.
There was one swine flu death in Southland.