The Māori Council is calling for a Royal Commission to investigate Pharmac and previous governments' failures to provide adequate funding.
Its chief executive, Matthew Tukaki, says many New Zealanders, especially Māori, can't afford life-saving and life-extending medications.
He said more than 100 people had reported side effects since Pharmac changed the brand of their mental health drugs.
Mr Tukaki said many medicines were also not approved in time for people who need them, including Maori.
"At the outset, the concerns of the New Zealand Māori Council were around the affordability factor of life-saving and life-extending medications when it came to our people," he said.
"From an economic perspective, and using breast cancer medications as an example, the non-scheduling of some medications is out of the realm of possibility for many whānau."
He said the council was also aware of other life-saving and life-extending medications that are not being supplied to New Zealanders, or had been changed.
"For example; Pharmac fund adrenalin but the not the EpiPen through which the drug is transmitted. Then there is the case of more than 45,000 New Zealanders who have been shifted from one mental health drug to another. While Pharmac argue that the drug mix is the same, but with a different brand, in a single year there were 142 reports of adverse side effects from those who had transitioned.
"The admission from the CEO of Pharmac in an interview with Radio New Zealand that she cannot be certain - that of that 142 who have experienced side-effects as a result of the switch, they may or may not have gone on to self-harm, attempt suicide or commit suicide - is a challenging statement to hear," he said.
He said Pharmac needed more funding, and the current model needed more transparency and efficiency.
Mr Tukaki said a Royal Commission was needed not just to test the veracity of the current model but to look at how it could be developed and adequately funded.