The NGO, the International Crisis Group, says conflict between Muslim and Christian communities in the Indonesian province of Papua could erupt unless rising tensions are effectively managed.
The group's latest report, explores the factors that have led to increasing strains in Papua.
Crisis Group's Senior Adviser, Sidney Jones, says the potential for communal conflict is high in Papua because both sides consider themselves aggrieved.
He says Indigenous Christians feel threatened by ongoing Muslim migration and a sense that the government is endorsing Islamic orthodoxy at the expense of non-Muslim minorities.
He also says Muslim migrants feel democracy may be leading to a tyranny of the majority, where in the long term they will face discrimination or even expulsion.
In 2005, tensions were high in the Manokwari and Kaimana districts on the west coast when Christians mobilised to prevent an Islamic centre and mosque from being built on a site the Christians considered holy.
The group says government officials at all levels - central, provincial and district - should avoid support for exclusive religious groups, and ensure that funding for all religious activities is fully transparent.