Tensions have been simmering between indigenous communities and oil companies in Ecuador since Texaco - now Chevron - began operations in the Amazon in the 1960s.
Hunter-gatherers in the Amazon sought in court on Thursday to stop Ecuador's government auctioning their land to oil companies, as tension mounts over the future of the rainforest.
In a lawsuit seen by the Thomson Reuters Foundation - which could set a precedent for other tribes opposed to drilling - the Waorani said the government did not properly consult them in 2012 over plans to auction their land to oil companies.
"We live on these lands and we want to continue to live there in harmony. We will defend them. Our fight is that our rights are respected," said Nemonte Nenquimo, a leader of the 2,000-strong Waorani.
"Our fight is not just a fight about oil. This is a fight about different ways of living. One that protects life and one that destroys life," said Nenquimo, from Pastaza province in the eastern Amazon.
Ecuador's energy and environment ministries - the respondents in the case - and hydrocarbon secretary were not immediately available to comment.
When President Lenin Moreno met Waorani leaders last year to hear their concerns, he said it was important to have a dialogue and reach a consenus.
Tensions have simmered between indigenous communities and oil companies in Ecuador since Texaco - now Chevron - began operations in the Amazon in the 1960s.
Ecuador is pushing to open up more rainforest and develop its oil and gas reserves in the hope of improving its sluggish economy and cutting its high fiscal deficit and foreign debt.
The constitution gives the government the right to develop energy projects and extract minerals on any land, regardless of who owns it, but requires that communities are consulted first and are properly informed about any projects and their impact.
Laws to regulate the consultation process have yet to be introduced - although the court case could push the government to do this, said Brian Parker, a lawyer with campaign group Amazon Frontlines, which is supporting the Waorani.
"The lawsuit is to ensure that the processes enshrined in the constitution are carried through to guarantee the Waorani rights to prior consultation and their rights to territory," said Parker, who is based in Ecuador.
"The fact that the Waoroni have a chance in court to be able to plead their case is in itself a very important step," he said, adding that a court victory would provide an "invaluable precedent" for other indigenous Amazonian tribes.
The government announced last year that it had divided swathes of forest up into blocs for auction, one of which - bloc 22 - covers the Waorani's ancestral lands, raising the spectre of pollution and an end to their way of life.
Hundreds of Waorani and other indigenous peoples arrived in Ecuador's eastern city of Puyo to witness the court hearing, which is expected to include several days of oral testimony from Waorani leaders, with a decision in the next few weeks.
Ecuadorians voted in a referendum last year giving broad backing to limits on oil production and mining in environmentally sensitive areas, among other issues.
In two landmark cases in 2018, local courts sided with indigenous communities who said the government had failed to inform them before designating their land for mineral exploitation.
The Costa-Rica based Inter-American Court of Human Rights also ruled in 2012 that Ecuador had violated its Sarayaku Amazonian community's right to prior consultation before drillers started exploration on their lands in the late 1990s.