Health workers are banding together to demand a sweeping review of what the Trans-Pacific Partnership could mean for the sector they work in if New Zealand signs up to the deal.
They say the government will be nothing short of medically negligent if it chooses not to have an assessment done.
It comes months after more than 270 health professionals sent an open letter to the Prime Minister about their concerns on 12 May. They say assurances they have received so far are vague, and they are not satisfied with the responses they have had.
Alex Macmillan, co-convenor of the Climate and Health Council, is one of six authors of a new article in NZ Doctor asking for a review.
"The government's job as a sovereign democratic state is to protect and improve the health of its population, of New Zealanders," she said.
"We know that the provisions at the moment are potentially really harmful to that so we do think that failing to take into account in a proper and transparent way, the potential implications for health, is essentially negligent."
Dr Macmillan said the TPP is dangerous and the article is a very strong statement of the concerns held by medical workers.
"While the government's reason for being is improving health and wellbeing as New Zealanders, that's not what these big companies are after, that's not what their purpose is.
"They're just very interested in us behaving and buying in certain ways that maximise their profits and this trade agreement is removing the government's role - its ability to make good laws and improve our health."
Trade Minister Tim Groser said New Zealand's trade agreements include provisions that protect the Government's right to regulate for legitimate public policy purposes, including public health, safety and the environment.
At the heart of the health workers' fears are lingering concerns that foreign corporates will be able to take legal action against New Zealand for measures like warning labels on alcohol or tobacco.
Director of Alcohol Healthwatch, Rebecca Williams, said her organisation was backing calls for a comprehensive review of the secret negotiations.
"All we're saying is we'd like it to be out in the open and we'd like it assessed against public health and against environmental health.
"We're not saying we don't want trade and we don't want agreements ... what we do want to be able to guarantee is New Zealand's sovereign right to protect health both of its people and its environment."
Ms Williams said significant public health issues the country is grappling with like obesity, tobacco control and alcohol reform will remain unless big measures are put in place to address them.
She said New Zealand must be in a position to make its own policies and interventions without being "undermined" by its trade relationships.
The push for a health impact assessment is also backed by the Medical Students Association.