The Vanuatu Christian Council has been refused permission from the government to hold a peaceful march in Port Vila against the country's accession to the World Trade Organisation.
All Christian churches had pledged to lobby MPs not to ratify the decision.
The Council says the government has not done enough to inform the public about what WTO membership entails.
The Council's Alain Nafuki says Vanuatu is too small to withstand being overwhelmed by WTO membership.
"And we think that to invite big multi-national companies to rule over this nation, we never know, they may come and indirectly change our legislation in Vanuatu and change most of our sectors in Vanuatu. So that is why we want to march."
Pastor Alain Nafuki says the Council will persevere with plans for a large public gathering.