PERU'S government has declared an environmental state of emergency in a remote Amazon jungle region it says has been affected by years of contamination at the country's most productive oil fields.
Indigenous groups in the Pastaza River basin near the Ecuador border have been complaining for years about the pollution and the failure of successive governments to address it.
Authorities say one reason the pollution was never addressed is that until now Peru lacked the requisite environmental quality standards.
In declaring the emergency, Peru's Environment Ministry on Monday said the contamination included high levels of lead, barium and chromium as well as petroleum-related compounds.
The region is inhabited mostly by the Quechua and Ashuar, who are primarily hunter-gatherers.
The fields have been operated for roughly 12 years by Argentina-based Pluspetrol, the country's biggest oil and natural gas producer, which will be obliged to clean up the contamination, Environment Minister Manuel Pulgar-Vidal said.
But the government also made clear that the field's previous operator, Occidental Petroleum, had not adequately remediated contamination either.
It began drilling there in 1971. Pluspetrol took over in 2001.
The 90-day emergency orders immediate action to reduce the risk of contamination to the local population. It follows an $US11 million ($A10.56 million) fine against Pluspetrol in January.
"We know that there has been bad environmental behaviour by the company," Pulgar-Vidal said.
Pluspetrol did not immediately respond to requests for comment.
Pulgar-Vidal did not describe the extent of the contamination or estimate what it would cost to clean up.
The Peruvian TV news program Panorama showed crude-permeated rivers and ponds in the area as well as the deteriorating oil pipeline that pumps crude to the Pacific coast.
The investigative weekly Hildebrand en sus Trece reported in 2010 that Pluspetrol had 78 oil spills in the region from 2006-2010, blamed for ailments including birth defects.