The suit targets President Rafael Correa, several serving ministers and other members of the executive branch, which the campaigners said have been promoting the mining and drilling in the region.

Efforts to expand oil exploration have seriously harmed the uncontacted tribes of Tagaeri and Taromenane who live in the remote territories, said the Confederation of Indigenous Nationalities of the Ecuadorian Amazon (CONAIE).

The oil and mining work was disrupting these people's fragile "absolute dependence" on the Amazon ecosystems, the group argued.

As a consequence, there was a process of "cultural and physical disappearance, which amounts to the crime of ethnocide or genocide".

It is the "first time we have presented a complaint of this type, which is also directed to an Ecuadoran president," CONAIE spokesperson Janeth Cuji told AFP.

While Correa enjoys immunity from criminal proceedings related to his current duties, the complaint was still able to move forward, Cuji said.

Relations between Correa and the group are already strained over new mining legislation the campaigners say would put water under the control of the mining and energy sector a claim the government denies.

There is no official data on the number of members in the Tagaeri and Taromenane tribes, or among other uncontacted people who live in the area.

But the figure is thought to be in the hundreds in larger communities.

Ecuador's indigenous population, however, accounts for about a third of the country's 14 million inhabitants.

Despite a history of violent clashes between indigenous groups and the state, there is also no record of genocidal efforts to exterminate the tribes.

Observers have long warned of the slow demise of nomadic peoples in the Amazon region due to the exploitation of their environment, both from illegal logging activity and from mining.