Indians protesting oil and gas exploration on their lands have battled police in Peru's remote Amazon, with authorities and Indian leaders reporting at least 30 deaths.

The violence broke out before dawn on Friday as officers tried to end a road blockade by about 5,000 Indians in an area called Curva del Diablo - or Devil's Curve - in the northern province of Utcubamba.

Protest leaders said police opened fire from helicopters with bullets and tear gas, while national police director Jose Sanchez Farfan said Indians attacked officers with firearms. He said they also set fire to government buildings.

Eight police officers were killed by gunfire and five wounded, said Interior Minister Mercedes Cabanillas.

Indian leader Alberto Pizango said 22 Indians were killed in the clash and he accused the government of "genocide" in attacking what he called a peaceful protest. Another 50 Indians were injured, 14 of them seriously, said Servando Puerta, president of a second indigenous umbrella group for the region.

Indians have been blocking roads, waterways and a state oil pipeline intermittently since April, demanding Peru's government repeal laws they say make it easier for foreign companies to exploit their lands.

The laws, backed by President Alan Garcia as he implemented the Peru-US free trade pact, open communal jungle lands and water resources to oil drilling, logging, mining and large-scale farming, Indians say.

Garcia, who wants to ramp up foreign oil investment in the Amazon, accused Pizango on Friday of "falling to a criminal level: assaulting a police post, grabbing arms from police, killing police who are fulfilling their duty".

Pizango denied that protesters killed police.

The government owns the rights to underground resources. A Duke University study published last year said contract blocks for oil and gas exploration cover about 72 per cent of Peru's rain forest.

Indians say Garcia's government does not consult them in good faith before signing such contracts, which could affect at least 30,000 Amazon Indians across six provinces.

Pizango said last month Indians would view any government security forces as an "external aggression" and would give their lives to defend the land.

Though he later rescinded what amounted to a declaration of insurgency, it is unclear how much influence Pizango, president of the Peruvian Jungle Inter-Ethnic Development Association, has over Indians in the conflict zone.

Garcia declared a state of emergency May 9 and suspended some constitutional rights in four jungle provinces as a result of the ongoing protests.

AP