A letter signed by 400 health professionals is urging the Government not to sign away New Zealand's ability to restrict the promotion of tobacco in negotiations over the Trans Pacific Partnership.
The 16th round of talks on the trade agreement starts in Singapore on Monday. The talks on a free trade deal involve the United States, New Zealand and nine other countries.
The letter to Prime Minister John Key says legal action by the tobacco industry against an Australian decision to move to plain packaging on cigarettes is an example of what could happen here.
Professor Jane Kelsey from the Auckland University Law School says leaks from the negotiations indicate the Government is willing to give away more than Australia was when it negotiated its free trade agreement with the United States.
She said the Trans Pacific Partnership Agreement is less about free trade and more about allowing commercial interests to influence the policies made by sovereign governments.
Te Ohu Rata O Aotearoa (Maori Medical Practitioners Association) chairman George Laking says protecting the commercial rights of tobacco companies should not be put ahead of protecting people's health.
He said tobacco is an addictive poison and shouldn't be treated in the same way as other goods traded between nations.