* Eradication efforts part of rebel "pacification" drive
* Peru's anti-drug stance aligns with Washington
* Humala's policy differs from other Latin American leaders
By Omar Mariluz and Terry Wade
LIMA, Feb 13 (Reuters) - Peru is intensifying its anti-drug efforts and will eradicate coca fields for the first time ever this year in a thicket of lawless jungle valleys where rebels often ambush soldiers, officials said on Wednesday.
Carmen Masias, the head of Devida, Peru's anti-drug agency, said the government would eradicate 22,000 hectares (54,000 acres) this year of coca, the main ingredient in cocaine. That would be a 56 percent increase from last year's record and push down overall coca production for the first time in decades, by about 6 percent.
Peru is virtually tied with Colombia as the top cocaine producer, with about 62,500 hectares (154,400 acres) of coca plants, according to U.N. data.
The eradication push - along with the construction of an airfield for anti-drug operations and an increased military presence - shows President Ollanta Humala, a former army officer, is moving ahead with promises to "pacify" a region known as the VRAEM.
The bundle of river valleys in southeastern Peru is the most densely planted coca growing area in the world - and the favored hideout of remnant bands of the Shining Path rebels who went into the drug trade after their leaders were captured in the 1990s.
Humala's toughening stance differs from a growing chorus of Latin American presidents who have questioned the U.S.-led "war on drugs" or called it a failure.
Citing "security reasons," Masias declined to say how much eradication work would occur in the VRAEM. But she stressed it would not be a token effort relative to Peru's numerous other coca growing areas.
Wresting control from the Shining Path in the VRAEM is crucial for Humala's economic plans as the area overlaps with Peru's main natural gas reserves, which the president has vowed to fully exploit to meet soaring domestic demand for electricity in the fast-growing country.
The rebels have so far mocked Humala's goal of stamping them out. Last year they captured 36 natural gas workers in their first large-scale kidnapping since 2003, leading Humala's interior and defense ministers to step down. About 17 soldiers were shot and killed last year in a series of ambushes by rebels, mostly in the VRAEM.
Masias said Peru must start wiping out coca farms in the VRAEM even if it results in violent retaliation by rebels and traffickers.
"These are the costs you pay when you aren't afraid of having a firm hand," she said.
Eradication in Peru is done manually, "plant by plant," and without the use of pesticides, Masias said.
CRITICS WORRY ABOUT 'MILITARIZATION'
Critics say Humala's eradication plan is risky.
"Militarization only leads to conflicts," said Nery Cuadros, a councilwoman from the Pichari district in the VRAEM. "The losers will be vulnerable people in the region - mostly peasants and indigenous communities."
Humala has dramatically reversed his earlier position on counternarcotics efforts.
Shortly after taking office in mid-2011, Humala appointed as drug czar Ricardo Soberon, who temporarily halted eradication work and drew criticism from the U.S. ambassador to Peru. Soon after, he was replaced by Masias.
Relations between Peru and the United States appear to have warmed considerably since Humala renewed anti-drug efforts.
A number of high-ranking U.S. officials have recently visited Peru - including Hillary Clinton when she was secretary of state, outgoing Defense Secretary Leon Panetta, and Marine General John Kelly, who leads military activities in South and Central America as the head of the U.S. Southern Command.
Soberon said Humala has been too willing to favor an anti-drug model advocated by Washington, one that may not be appropriate for Peru. Farmers in the VRAEM often plant a mix of cocoa, coffee and coca.
"The mere mention of eradication in the VRAEM is causing an adverse reaction in local communities," he said. (Reporting By Terry Wade, Mitra Taj, Omar Mariluz and Patricia Velez; Editing by Eric Beech)