Pharmac says it has saved $100 million since 2014 by doing deals to cut the price of medical devices, and spent under $10m achieving that.
As well as buying drugs, Pharmac has national contracts for 150,000 types of devices, from tongue depressors to hip implants.
The Pharmac review in June found savings had been much harder to find than expected, and recommended Pharmac give up the device management job to Health NZ - Te Whatu Ora.
But the government rejected that.
Now, Pharmac, in its interim response to the review, says managing medical devices is a strong fit with its capabilities.
"Since the first national contract was signed in 2014, we estimate the cumulative savings delivered for the health and disability sector is just over $100 million," it said.
"Savings, however, were not our primary focus; other benefits have included consistent access and standard supply terms (including nationally consistent pricing), reinvestment of freed-up funds into new technology, as well as sustainability and transparency."
By contrast, the June review said Pharmac was "ill-placed" to co-ordinate the extremely complex medical devices supply chain, and had yet to set up a way to weigh the technical benefits of medical devices.
In an OIA response to RNZ, Pharmac put the savings it had achieved at $101.8m - with $30m of that secured in the past year alone.
It put its outlay on staff who were in charge of the long list of contracted devices, and other expenses in running the system since 2014, at $8.7m.
"Pharmac's medical devices national contracting provides other benefits including creating more visibility of what medical devices are being used by each district, management of supply risks, and access to consistent pricing through standard terms and conditions," it said.
It has yet to provide documents RNZ asked for in July, about where its work to establish a process for undertaking health technology assessments is at.