Concern has been raised over the potential impacts the Pacific regional trade agreement PACER-Plus could have on the environment.
About 40 civil society organisations, including a number of environmental groups, have signed a letter calling for the negotiations to be suspended.
Representatives from Australia, New Zealand and 14 Pacific nations are meeting in Port Vila this week for the next round of negotiations, which began in 2009.
Hugh Govan, of the Fiji-based Locally Managed Marine Area Network, says there needs to be an assessment of potential environmental impacts of PACER-Plus.
Dr Govan says it is not known what the deregulation of outside investment could mean for Pacific resource management systems.
"If we are going to play with the big boys I think there should be much more investment in the environment department, to be able to regulate the development such as mining, logging, or even tourism industry and so on. The discussions need to go as far as possible in terms of how these sort of safe guards could be in any future agreements."