The summit of Amazon Cooperation Treaty Organisation (ACTO) members in the Brazilian city of Belem could agree to a regional pact to stop deforestation by 2030, end illegal gold mining, and cooperate on cross-border policing of environmental crime.
Leaders are expected to announce the final agreement, known as the Belem Declaration, late on Tuesday afternoon.
Presidents from Bolivia, Brazil, Colombia, Guyana, Peru and Venezuela will attend, while Ecuador and Suriname is sending other representatives.
On the campaign trail last year, President Luiz Inacio Lula da Silva pledged to convene the summit, as part of his bid to restore Brazil's environmental leadership after deforestation soared under his predecessor Jair Bolsonaro.
A Brazilian government source said the Belem Declaration will likely include financing mechanisms for sustainable development, provisions for including Indigenous leaders in policymaking, and shared strategies for tackling deforestation.
Whether an agreement can be reached on ending deforestation by 2030 will likely hinge on Bolivia, where destruction has increased recently due to fire and rapidly expanding farming.
ACTO Executive Director Carlos Lazary said the final agreement may include Brazil's plans for a regional centre in Manaus where Amazon countries can coordinate police operations.
The final agreement is likely to protest what the region sees as unfair trade barriers implemented in the name of environmental protection, CNN Brasil reported, citing a leaked draft of the declaration. The European Union recently passed a law prohibiting companies from importing beef, soy, cocoa and other products linked to deforestation.
On Wednesday, Amazon countries will meet with leaders of the Congo, the DRC and Indonesia, looking to issue a joint statement from the world's three major rainforest basins. Norway and Germany, which have funded Amazon preservation, and France, which controls the Amazon territory of French Guiana, will also participate.