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MEXICO CITY, March 13 (Reuters) - Support has fallen for the favorite to be Mexico's next president, Enrique Pena Nieto , of the opposition Institutional Revolutionary Party (PRI), even though his main rival is struggling to gain ground, a poll showed on Tuesday.
The latest survey of public opinion for the July 1 presidential elections from pollster Consulta Mitofsky showed the 45-year-old Pena Nieto with 38.5 percent support, down two percentage points from a poll published two weeks ago.
This enabled Josefina Vazquez Mota, of President Felipe Calderon's National Action Party (PAN), to close slightly on Pena Nieto, although her backing of 24.2 percent was also down from the previous poll, by half a percentage point.
Leftist candidate Andres Manuel Lopez Obrador, who lost to Calderon by a whisker in a 2006 election, inched forward slightly but remained in third place on 17.8 percent.
The results of the latest Mitofsky poll showed that fewer voters were decided about who they wanted to win than before.
The telegenic Pena Nieto carries the hopes of the centrist PRI, which is seeking to end 12 years on the sidelines. The PRI ruled Mexico for 71 years until 2000, a reign its opponents have derided as corrupt and authoritarian.
Pena Nieto has led polls for more than two years, but support for him has been declining for several months and his standing took a knock in December when he stumbled into a series of gaffes.
The latest results factor - in a lack of campaigning due to a month-long ban imposed by Mexico's electoral institute. This started in mid-February and will shut down most media exposure for all presidential hopefuls.
Mitofsky surveyed 1,000 people older than 18 years. The margin of error was 3.1 percent, the polling organization said. (Reporting By Anahi Rama and Cyntia Barrera Diaz; Editing by David Brunnstrom)
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