By Anahi Rama
MEXICO CITY (Reuters) - Mexico's presidential front-runner, Enrique Pena Nieto, has extended his lead and the opposition Institutional Revolutionary Party (PRI) he represents could gain an absolute majority in the lower house of congress, a survey showed.
Consulta Mitofsky said on Tuesday its latest opinion poll for the July 1 presidential vote showed Pena Nieto extending his big lead with 40.2 percent support, up 1.1 percentage point from the polling firm's survey published on March 13.
He was followed by Josefina Vazquez Mota, of the ruling National Action Party (PAN), at 22.6 percent. Her support dipped by 0.9 percentage point from the previous poll.
She is struggling to shake off discontent with the PAN, whose popularity has suffered due to the surge in violence that followed President Felipe Calderon's offensive on drug gangs, which he launched soon after taking office in December 2006.
Leftist Andres Manuel Lopez Obrador, who narrowly lost to Calderon in the 2006 elections, remained in third place at 17.3 percent, down 1.2 point from the March survey.
Excluding voters who were undecided or expressed no preference, the poll gave Pena Nieto effective support of nearly 50 percent, with Vazquez Mota at 28 percent.
Pena Nieto has led polls for more than two years and the PRI hopes he will return the party to power after more than a decade on the sidelines. The latest Mitofsky poll suggested the PRI could capture a majority in the lower house.
The centrist PRI ruled Mexico for 71 years straight until it was ousted by the PAN in 2000. The long reign was marred by allegations of corruption and authoritarianism.
Pena Nieto, the 45-year-old former governor of the State of Mexico, which adjoins the capital, has had some problems in the campaign, but they have not done major damage to his bid.
He made several gaffes at the end of 2011, most notably when he struggled to name three books that influenced him. And in January, he had to admit he had cheated on his first wife, fathering two children out of wedlock with different women.
Yet voters believe he is most likely to end the drug violence that has claimed more than 50,000 lives in the past five years, and reinvigorate the Mexican economy, which has underperformed regional peers over the past decade.
Mitofsky's data showed the PRI was on track to win 49.5 percent of votes in the lower house. Adding the environmentalist Greens, a small party running jointly with the PRI, support was 51.3 percent, the highest this year, the figures showed.
No party has held a majority in congress for 15 years, and investors are hoping a big win for the next president could clear the way to pass stalled economic reforms in Mexico.
Vazquez Mota's campaign has been undermined by squabbling inside the PAN, as well as a number of mishaps on the election trail. Lopez Obrador is still trying to win back voters he alienated with massive, disruptive street protests in the capital after his disputed narrow loss to Calderon in 2006.
Mitofsky surveyed 1,000 people 18 and older. The margin of error was plus or minus 3.1 percent, it said.
(Writing by Dave Graham; Editing by Eric Walsh)