Health professionals are urging the Government to consider the consequences of the CPTPP before it's ratified into law.
The New Zealand Climate and Health Council (OraTaiao) says a comprehensive health impact assessment of the CPTPP (Comprehensive and Progressive Agreement for Trans-Pacific Partnership) should be undertaken.
Representatives will speak at a select committee hearing this week advocating for changes.
OraTaiao co-convenor Rhys Jones says it's risky to make the CPTPP official now.
"We could see effectively future Governments being prevented from putting in place the type of polices, the type of legislation that might be needed to address some of the risks coming down the track."
Mr Jones, a senior lecturer in Māori Health at the University of Auckland, says there would be enormous implications for health and social justice if New Zealand enters it.
"From the perspective of climate change and health, we actually believe the agreement is incompatible with what we need to do to address climate change."
Eleven countries signed the CPTPP - Australia, New Zealand, Canada, Brunei, Chile, Japan, Mexico, Malaysia, Singapore, Peru and Vietnam. The US pulled out when Donald Trump became President.
Submissions on the controversial deal closed in April. Supporters say it will bring billions in trade to the New Zealand economy.