The pharmaceutical industry is backing calls from the United States to overhaul Pharmac in trade talks with New Zealand.
The US government has revealed its position on New Zealand's drug-buying agency in the latest round of the nine-country TransPacific Partnership trade talks.
After months of lobbying by senators and the industry, the US finally revealed its position at negotiations in Chicago last week.
It is calling for greater transparency and procedural fairness from drugs-buying agencies like Pharmac.
Critics say this means having to reveal sensitive information which would inhibit its ability to get the best value for money from drugs purchases.
But Medicines New Zealand, which represents the industry, says Pharmac should be no different from other government departments when calling for tenders.
This means full engagement with suppliers and the right to appeal against decisions, it says.
US industry dictating talks - CTU
The Council of Trade Unions says the US government is falling in behind demands from the medicines industry to undermine Pharmac in trade talks.
CTU economist Bill Rosenberg attended the talks in Chicago says the demands match those of the American pharmaceutical industry.
Mr Rosenberg says if New Zealand caves into these demands, Pharmac's ability to get the best value for money for drug purchases could be undermined.
But the NZ-US Council says the demands are unlikely to be detrimental to Pharmac.
Executive director Stephen Jacobi says the US has 40 similar drug purchase agencies and is also concerned with minimising the cost of drugs to its population.