The Pacific Network on Globalisation says it believes the European Commission has strong-armed Fiji into ratifying a free-trade agreement.
The group, which is known as PANG, says it is very concerned by Fiji's announcement it will provisionally apply an Economic Partnership Agreement, or EPA, with the European Union.
PANG's co-ordinator, Maureen Penjueli, says Fiji has no choice but to go with the agreement or it will lose market access to Europe, which could affect key industries such as sugar.
"We are quite concerned about many of the toxic and contentious issues that are still contained within the interim EPA that Fiji has signed up to. The Fiji Government is fully aware of what these toxic and contentious issues are but our view is that they ratified under duress."
Maureen Penjueli says some of those toxic issues include export taxes and the absence of a development component.
Ms Penjueli says the European Commission uses economic partnership agreements to secure market access for raw materials for its own development.
Meanwhile, the EU has said Fiji's decision is a very significant step as the EPA is one of the main EU tools to assist developing countries, such as Fiji.