University of Otago academic Prof Pauline Norris is concerned New Zealand's overall drug costs will rise under the proposed Trans Pacific Partnership agreement.
Prof Norris, of the university School of Pharmacy, said New Zealand's use of the Crown drug-buying agency Pharmac meant "much lower prices'' for drugs here than in many other countries.
Her main worry was that, under the TPP agreement, Pharmac's effectiveness in keeping prices down could be reduced.
"I'm very worried about the impact on New Zealand's ability to pay for medicines and the impact on the whole health service if we had to pay a lot more for medicines.''
Prof Norris noted the international humanitarian group Doctors Without Borders had recently raised serious concerns about the TPP and its role in delaying access to cheaper generic versions of drugs, by extending previous intellectual property protections.
Delaying access to generic drugs was also likely to adversely affect New Zealand, she said in an interview.
New Zealand had limited overall health funding, and any money spent on paying for costlier drugs would ultimately not be available to meet other important needs, she said.
She was also concerned about aspects of the investor-state disputes settlement process under the TPP.
This raised the prospect that big companies could sue governments, including if they felt their intellectual property was at risk.
And the prospect of legal action could have a "chilling effect'' on potential government action to make health policy improvements.
Prime Minister John Key has previously acknowledged that extending the drug patient protection period under the TPP would delay access to cheaper generic drugs, but has said the Government would ensure patients would not pay more for medicines.
There could be a small increase in funding for Pharmac, but this would be far outweighed by extra income from taxes the Government would receive under the TPP deal, Mr Key has said.
