Two gold miners have reportedly been arrested after about 10 members of an uncontacted Amazon tribe were allegedly killed in a massacre.

The incident happened last month on the River Jandiatuba in Brazil’s west and included women and children as victims, according to tribal peoples’ rights group Survival.

It was only reported to Brazilian authorities after two gold miners were apparently heard ‘boasting’ about the deaths and paraded "trophies" from the massacre in a town near where the killings happened.

Agents from Brazil’s Indigenous affairs agency FUNAI shared details of the incident with Survival.

The region is dubbed the ‘Uncontacted Frontier’ because it is home to the highest number of tribes living without ties to the outside world.

The agency was investigating and had alerted Brazil’s public prosecutions office who had launched their own enquiry into the reports.

FUNAI’s Leila Silvia Burger Sotto-Maior described the way the alleged attackers spoke about the incident as “crude bar talk” to the New York Times.

“They even bragged about cutting up the bodies and throwing them in the river,” she said.

Ms Sotto-Maior said the suspects arrived at a bar close to Brazil’s border with Colombia with a hand-carved paddle they claimed had been taken from the tribe.

Survival director Stephen Corry said Brazil’s president Michel Termer and his government bore ‘a heavy responsibility for this genocidal attack’ if the reports were true.

“The slashing of FUNAI’s funds has left dozens of uncontacted tribes defenceless against thousands of invaders – goldminers, ranchers and loggers – who are desperate to steal and ransack their lands,” Mr Corry said on the organisation's website.

“All these tribes should have had their lands properly recognised and protected years ago - the government’s open support for those who want to open up indigenous territories is utterly shameful, and is setting Indigenous rights in Brazil back decades.”