The Health Minister is standing by the Pharmac model despite calls for an inquiry into its processes.
On Wednesday, the National Party's Health spokesperson Michael Woodhouse will call on Parliament's Health Select Committee to launch an inquiry into Pharmac.
It comes after repeated calls for the company, which decides which drugs are subsidised for Kiwis in public hospitals, to fund breast cancer drugs Ibrance and Kadcyla.
Ibrance has been called a life-extending drug, and allows patients to work while taking it and avoid chemotherapy.
It is funded in Australia, and last month, Breast Cancer Foundation chief executive Evangelia Henderson told Newshub it should be in New Zealand. One advocate is currently paying nearly $6000 a month for the Ibrance privately.
While Pharmac is considering funding the medicine, some experts say it is taking too long and people are dying in the meantime.
Woodhouse said the public deserves answers and there are three key processes of Pharmac that should be looked into.
"One is the level of funding, the other is the level of transparency in their decision-making, and the third is the time it takes them to make those decisions," he told Newshub.
Health Minister David Clark told The AM Show he has written to the agency, asking it to consider the transparency and timeliness of its processes, but still stands by the model.
My view personally is that the Pharmac model works and that it needs to be supported to work
"I also support and have encouraged obviously, that they look at the transparency and timeliness of their processes. To me that is the priority."
Clark said it is up to the select committee to decide if an inquiry was needed, but he doesn't support politicians interfering.
"Ultimately, these decisions are made by clinical experts and I think it is really important that politicians don't second-guess those clinical decisions," he said.
"[The select committee members] know, as I am telling you and as I have said in public many times, that I don't think an inquiry is the productive way of going about it."
He said he was moved by stories of women struggling to afford treatment for their cancer and wants to ensure the correct evidence is being put forward to make the health system stronger.
That means keeping the agency at arm's length from him as minister.
I absolutely accept it is deeply personal, and the principle I will come back to is that I don't think it is for politicians to second-guess this
"People have confidence in the Pharmac model as a whole, the public does, because it is independent, because it is expert-driven and because it gets the value that it gets.
"It might be politically expedient for me to have an inquiry, but I actually think we need to focus our resources on making sure that the health system is performing and responding."
Clark couldn't provide any timeline for when those battling cancer will find out if the drug will be funded, but trusts those making the decisions.
"They have been investigating these drugs for a while now, but I don't control that process because it is important that it is done by clinicians and that they have the best evidence and they can make the decision based on the evidence.
We can't control the drug companies and when they supply the evidence and how they do the negotiation from their end.
Petitions calling on Clark to work with Pharmac to fund Ibrance and Kadcyla received 29000 and 1500 signatures, respectively, and were delivered to Parliament last year.