FÉLIX JIMENEZ, JEFE DE PLAN DE GOBIERNO DE GANA PERÚ, HABLA CON REUTERS

(Reuters) - Nationalist presidential front-runner Ollanta Humala wants economic stability for Peru if elected in June and will not follow the path of left-wing leaders in Venezuela and Bolivia, his top advisor said on Wednesday.

Peru's benchmark stock index sank 6.2 percent and its sol currency weakened further on worries about Humala's first-round win on Sunday.

A former army officer turned populist, Humala will face right-wing lawmaker Keiko Fujimori in a run-off on June 5.

"This has nothing to do with (Venezuelan President Hugo Chavez), nothing to do with Bolivia," Humala's economic advisor, Felix Jimenez, told Reuters. "Economic stability is very important for consolidating growth."

Humala, who says wealth from a decade-long boom has failed to benefit a third of Peruvians living in poverty, moved to the center after narrowly losing the 2006 race and tries to emulate Brazil's moderate former president Luiz Inacio Lula da Silva.

But many Peruvians still regard Humala as an unpredictable radical who led a brief military uprising in 2000, much like Chavez did in 1992, six years before he was elected.

A professor at Lima's Catholic University and a former director in the Finance Ministry's debt department, Jimenez said Humala has categorically ruled out taking over private companies -- unlike Chavez and Bolivian President Evo Morales, who have taken over banks and oil firms.

"There's not going to be anything like state takeovers or expropriations," Jimenez said. He did, however, say Humala favors renegotiating some contracts held by mining and natural gas firms, so they would pay more taxes to the government and, in the case of gas, give priority to domestic consumers over exports.

Many miners have what amount to special tax treaties with the government, which gives them preferential treatment and protect them from tax hikes, though most of the pacts were signed in the 1990s and will start expiring next year.

Jimenez got his doctorate in economics at the New School in New York, which says on its web site it teaches "a wide range of schools of thought, including Keynesian and post-Keynesian economics" alongside neoclassical economics.

In an interview, Jimenez appeared to endorse part of a set of policies that are sometimes called "resource nationalism."

"Nationalization is a type of political proposal that means that extractive industries should work toward national development," he said. "The exploitation of non-renewable natural resources should serve the country so we can develop."

Firms in Peru's vast resources sector should pay royalties and windfall profits taxes, plus existing levies, he said. Any changes could potentially impact global giants like Southern Copper, Xstrata and Newmont.

Right now, Peru's tax take is merely 15 percent of gross domestic product, leaving the state relatively weak and unable to finance education and health care programs.