MEXICO CITY (Reuters) - Rules adopted by Mexico's ruling Institutional Revolutionary Party to allow it to form coalitions and non-members to run for president were necessary to stop leftist Andres Manuel Lopez Obrador from winning office next year, its president said.


The rules adopted over the weekend give the once-dominant party, known as PRI, a better chance of clinging to power in the July presidential election, where veteran leftist Lopez Obrador is an early favorite among voters tired of graft scandals, violence and a tepid economy.


PRI President Enrique Ochoa called Lopez Obrador "the enemy to beat," repeating a long-standing refrain by Mexico's ruling class that he would wreck the economy with Venezuelan-style policies.


"He is the threat for Mexico going forward," Ochoa said in an interview on Foro TV. "We don't want to have the same fate as Venezuela, with food shortages, the highest inflation in the world and GDP falling by 7 percent."


Since last year, Mexico has been more concerned about a possible rupture of trade ties with the United States under Donald Trump than domestic politics, but the government has grown confident in recent months that talks starting this week in Washington will not end the North American Trade Agreement, which underpins much of Mexico's economy.


Lopez Obrador recently denied having anything to do with the Venezuelan government. On the two previous occasions that the former Mexico City mayor ran for president, his opponents used the same strategy of comparing him with Venezuela's socialists.

Ochoa said the new party rules allowed any future PRI president-elect to form coalitions to "foment governability." He did not rule out alliances with any major party, beyond saying coalitions should be with those the centrist PRI could identify with ideologically.

Party veteran Mario Fabio Beltrones proposed allowing coalitions. The rules allowing non-party members to run for president are widely seen as favoring Finance Minister Jose Antonio Meade, a technocrat untainted by the corruption scandals that have eroded the popularity of Pena Nieto's government.

Meade has served in governments of both the PRI and the conservative opposition National Action Party. He is not a member of either party.

(Reporting by Frank Jack Daniel; Editing by Lisa Von Ahn)