By Christine Murray

By Christine Murray

(Reuters) - Mexican presidential front-runner Andres Manuel Lopez Obrador has extended his lead well beyond his nearest rivals with just a month to go before the July 1 election, an opinion poll showed on Thursday.

The survey by polling firm Parametria showed support for the leftist former mayor of Mexico City at 45 percent, an increase of six percentage points from a prior April poll. That gave Lopez Obrador more backing than his nearest two rivals combined.

Lopez Obrador, 64, was runner-up in the previous two elections, with fears that he could destabilize the economy contributing to his defeat. This time frustration over corruption, rising violence and tepid growth have all helped lift his bid.

 

Lopez Obrador's closest competitor is Ricardo Anaya, a former chairman of the center-right National Action Party (PAN), who is fronting a right-left coalition of parties.

However, support for Anaya slipped 5 percentage points to 20 percent, in spite of the May 16 withdrawal from the race of former first lady and onetime PAN member Margarita Zavala.

"Anaya was expected to go up because of Margarita quitting, but it seems that the one who benefited was (Lopez Obrador)," Parametria founder Francisco Abundis said.

Holding steady at 14 percent support in third place was former finance minister Jose Antonio Meade, the candidate of President Enrique Pena Nieto's Institutional Revolutionary Party, or PRI. The law prevents Pena Nieto from running again.

The fourth candidate on the ticket, independent Jaime Rodriguez, dipped one point to 1 percent. Rodriguez was fined this week for raising illicit campaign funds.

All told, 17 percent of respondents expressed no preference in the latest poll, which followed a separate survey by newspaper Reforma published on Wednesday that gave Lopez Obrador support of more than half the voters.

Parametria said its poll consisted of 1,000 face-to-face interviews and was conducted from May 23-29. The poll had a margin of error of 3.1 percentage points.

The silver-haired Lopez Obrador has pledged to root out corruption and reduce violence, as well as re-invigorate the domestic economy and address chronic inequality if elected.

His room for maneuver as president will depend considerably on how much control his National Regeneration Movement (MORENA) party can exercise in Congress.

The latest poll showed increasing support for MORENA, but it is unclear whether the party will have an outright majority. No party has held an absolute majority in Mexico since 1997.

Support for MORENA and its two main allies came to about 37 percent in the lower house and 39 percent in the Senate. Once undecided voters are stripped out, the percentage rises.

(Reporting by Christine Murray; Writing by Dave Graham; Editing by Leslie Adler)