Sir Bob Elliott fights for cystic fibrosis drug Trikafta to be made available in New Zealand

The doctor who's saved thousands of lives and impacted millions of people around the world has one last fight before his own life ends.

Sir Bob Elliott, the medical mind behind the heel prick test to assess babies for cystic fibrosis, is dying from cancer. But he's trying to make a million-dollar miracle cure for the condition available for everybody who needs it in New Zealand.

After a lifetime of treating and caring for people with cystic fibrosis, he finally has a cure on his hands in the form of Trikafta, a drug that's been called a "miracle" by those with the condition who have taken it.

The drug is made by American company Vertex, which charges people nearly $500,000 for a year's supply.

"But we face this problem of a drug that works, but nobody can afford it. It's about $470,000 per year. You'd have to be the child of Jeff Bezos to afford that sort of amount of money," Elliott told The Project.

He's bought 17-year-old Bella Powell a three-month supply of the drug, and she says it's changed her life.

"You can't put into words the amount of faith that man has had in me my whole life," she says.

"I will never be able to repay him for everything he's done for me."

Elliott spent about $100,000 to pay for Powell's supply of Trikafta, a price he says is "unethical".

"I know they've done a fabulous job in coming up with this formulation, it's been a long haul for them and an expensive one. But as a practising doctor it just upsets me that this marvellous treatment is being dangled in front of people, [saying] 'if you took this you'd be okay, but you can't afford it'," he says.

"My life has been built around trying to help people with the illness, but I'd do it for nothing. The money is very secondary to me. But obviously it's not to a drug company who wants to not only recover the money they've spent developing the drug, but also wants to make a massive profit."

Powell's mum Alley says although the drug comes at a high cost, the outcomes are something you can't put a value on.

"[Bella] is walking the dog down the beach, haven't done that for years. That's something I never thought I'd see again. But I have."