Quito, Oct 4 (IANS): Ecuador's Congress approved oil drilling in the nation's biggest oil field in Yasuni National Park, part of the Amazon reserve, media reports said.

After a long-time debate, the government-dominated Congress Thursday authorised President Rafael Correa's plan by a 108 to 25 margin, which gave green light to oil drilling in blocks 31 and 43, with conditions attached to minimise the impact on both the environment and local tribes, reported Xinhua.

Correa said about $20 billion of the earnings would be used to combat poverty in his country.

He added that it is essential to expand oil reserves to increase government spending on the poor.

However, there have been protests from indigenous groups and environmentalists since Correa announced in August that he was abandoning the Yasuni plan, which persuaded rich countries to pay Ecuador to avoid its exploitation.

So far, about 680,000 people have signed a petition calling for a referendum.

The president launched the plan in 2007 to protect the Yasuni National Park, which boasts some of the planet's most diverse wildlife, but scrapped it this year after raising only $13 million out of the expected $3.6 billion, saying wealthy countries had "failed" Ecuador.

The oil believed to be lying under the Yasuni is equivalent to 20 percent of the total reserves of Ecuador, OPEC's smallest member. It's unclear when the drilling would begin.