A cancer specialist has warned that if medicine patents are extended under the Trans-Pacific Partnership deal, patients will have to wait longer for the drugs they need.

Christchurch oncologist Bernie Fitzharris told Nine to Noon patients were already dying waiting for new drugs to be funded by the Government's drug buying agency Pharmac.

Dr Fitzharris said, for instance, there was a new drug to treat malignant melanoma but it was not yet available under the public health system.

He said 300 people died of malignant melanoma each year. Patients would benefit from using the new drug but it cost $100,000 to $200,000 annually for each person. In total that would cost the drug-buying agency Pharmac $30 million to $60 million a year.

Dr Fitzharris said that under TPP it was likely getting access to these new, more effective drugs would be delayed even further.

Medicines New Zealand says the most recent OECD report shows New Zealand comes last out of 20 countries when it comes to access to new medicines.

Of all available new medicines approved for use in this country by Medsafe just 13 percent are funded by Pharmac.

Radio New Zealand has been contacted by patients who are paying for their own medicine because it was not on Pharmac's subsidised list.

Photo: RNZ / Alexander Robertson

They said Prime Minister John Key was wrong to insist New Zealanders would not be disadvantaged by the TPP deal.

At the very least if patents are extended these people would have to pay for their medical treatment for much longer.

Labour Party health spokesperson Annette King said it was also likely that as other new generation drugs were developed New Zealand would wait even longer for them to become available here.

"New Zealanders are going to have to pay higher for their drugs and the second issue is some people are going to pay with their lives.

"Because if they extend the patent, particularly on drugs for cancer and for heart disease, and we can't get access to the generic drugs for longer then people are not going to get that access and they won't have the opportunity to extend their lives," said Mrs King.