The Ministry of Health spent $37 million on personal protective equipment (PPE) that was not fit for purpose.
Its annual report for the year ended June shows the health agency spent a total of $108m on PPE for frontline staff in response to the spread of Covid-19.
The equipment included face masks, face shields, gloves and protective clothing.
However, this cost includes a $71.5m write down in the value of the PPE it had on hand.
About $37m of which was spent on PPE which was defective or raised quality concerns, while the remaining $34.5m was a result of equipment that was bought when prices were at a premium.
The ministry has been approached for comment.
Association of Salaried Medical Specialists union head Sarah Dalton said the defective equipment was a consequence of not enough proactive investment in the public health sector, which left the ministry the back foot when Covid-19 emerged.
"There's always the potential, when you're having to order large amounts quickly of gear like that, for there to be a few trips along the way.
"But I think part of the issue here is that we haven't as a country invested in proactive public health capacity over quite a long period of time."
She commended those working in the public health sector, but added that there were not enough of them.
Dalton said there was also a need for transparency around which PPE manufacturers were being used, and called for quality control measures to ensure equipment worked as it should.