MEXICO CITY (Reuters) - Mexican presidential front-runner Enrique Pena Nieto has widened his big lead over struggling ruling party candidate Josefina Vazquez Mota, with just 2 1/2 months to go until the July 1 election, an opinion poll showed on Sunday.
The latest voter survey by polling firm BGC for Mexican newspaper Excelsior showed support for Pena Nieto, a member of the opposition Institutional Revolutionary Party (PRI), running at 50 percent, according to BGC's Website.
That score was 3 percentage points higher than a previous BGC/Excelsior poll published on March 26.
Vazquez Mota, the candidate from President Felipe Calderon's conservative National Action Party (PAN), slipped one point to 29 percent. Third placed contender and 2006 runner-up, leftist Andres Manuel Lopez Obrador, fell back two points to 20 percent.
Pena Nieto has led the polls for more than two years and is widely expected to put the PRI back in power after more than a decade on the sidelines. The centrist faction ruled Mexico for 71 years straight until the PAN ousted it in 2000.
Pena Nieto, 45, has had his share of troubles along the way.
The ex-governor of the State of Mexico, a populous region flanking the capital to the north, made a number of gaffes at the end of 2011, most notably when he struggled to name three books that influenced him.
In January, he admitted he cheated on his first wife, fathering two children out of wedlock with different women.
But none of this has done lasting damage to his bid, because voters believe he is more likely to end the violence plaguing Mexico and reinvigorate the economy.
Vazquez Mota is trying to shake off discontent with the PAN, whose reputation has suffered due to a surge in lawlessness that followed the army-led offensive Calderon launched against drug gangs shortly after he took office in December 2006.
More than 50,000 people have since been killed in fighting between the gangs and their clashes with security forces.
Many of the victims have been young people lured by the prospect of quick cash from the gangs. The PAN has also struggled to create enough jobs for Mexico's growing population.
Vazquez Mota's campaign has been undermined by squabbling within the PAN, as well as a number of mishaps on the election trail, including the botched staging of a major rally last month that left her addressing a half-empty stadium stands.
Lopez Obrador, the former mayor of Mexico City, is still trying to win back voters he alienated after his narrow loss to Calderon in 2006. He accused the PAN of robbing him and declared himself the rightful president of Mexico, launching massive street protests in the capital that eroded his support.
The latest poll for Excelsior surveyed 1,200 registered Mexican voters from Monday through Wednesday and had a margin of error of 2.9 percentage points, BGC said.
(Reporting by Dave Graham; Editing by Stacey Joyce)