A Samoan environmental organisation, O le Siosiomaga, says the Pacific Ocean should not become a dumping ground for climate change fighting experiments.
The German research vessel, Polarstern, is on its way to the Scotia Sea to begin a large scale ocean fertilisation experiment, called Lohafex.
It'll add iron to the ocean to cause large algal blooms, which could absorb carbon dioxide as they grow.
It's seen as a possible solution to global warming and could be used for carbon trading schemes.
But the organisation's executive director, Fiu Elisara, condemns this controversial German/Indian experiment because its impact on the marine ecosystem is unclear.
"It's a new issue here, especially in the Pacific. There're a lot of things we still need to understand, especially when we have the Pacific Ocean as being targeted as a dumping ground for these nanoparticles. We need to be very, very sure that it'll create benefits rather than negative impacts to our resources."
Fiu Elisara says Pacific nations must reject flawed solutions to climate change.
German media quote the country's environment minister, Sigmar Gabriel, as saying it defies a United Nations agreement signed last year, prompting him to call for a halt.
But the German research institute, the Helmholtz Association, says its assessment shows the experiment will cause no environmental damage.