Mexico's presidential hopefuls wrap up campaigns ahead of historic election

MEXICO CITY, May 29 (Reuters) - Mexico's presidential candidates are set to formally end their campaigns on Wednesday ahead of Sunday's election, in which polls show ruling party candidate Claudia Sheinbaum on course to become the country's first woman president.

Latin America's no. 2 economy will hold its largest election ever, with more than 20,000 positions up for grabs and almost 100 million Mexicans eligible to vote.

In addition to the presidency, voters will fill both chambers of congress, the mayor of the capital Mexico City, eight governorships, local congresses and thousands of other positions.

Sheinbaum, a former Mexico City mayor, will close her campaign in the capital's Zocalo square on Wednesday afternoon alongside her party's mayoral candidate for Mexico City, Clara Brugada.

Brugada is vying to maintain the left's hold on power in the metropolis, which leftists have controlled since voters began electing its mayor 27 years ago.

Sheinbaum, a 61-year-old scientist and close ally of current President Andres Manuel Lopez Obrador, says it is "time for transformative women" while promising "change with continuity."

The frontrunner has spoken of adjusting policy around key issues including energy, security and corruption, but has avoided showing differences with Lopez Obrador.

"We are going to uphold the legacy of our great president," she said at a recent rally.

Sheinbaum has assured she will be the one to govern if she wins, but some say her political mentor would loom large.

Meanwhile, Xochitl Galvez, the standard bearer of an opposition coalition, will close out her campaign in Nuevo Leon, in Mexico's northern industrial heartland, days after she led a massive rally in the capital.

Galvez trails Sheinbaum by up to 20 percentage points, according to polls.

The 61-year-old former senator and businesswoman has promised to improve and expand social programs as well as fight corruption and the widespread violence unleashed by organized crime, in a country where intentional homicides have surpassed a record 185,000 in Lopez Obrador's term.

"Millions of Mexicans are going to go out to vote against authoritarianism, against lies, against violence, against division," Galvez said at a rally this week. "They are going to have the bravest president."

Lopez Obrador has called Sunday's vote a referendum on his political project, which has won him enormous popularity with social programs targeting the poorest segments of Mexico's population.

Whoever wins will face challenges on multiple fronts, including rampant impunity amid high murder rates and enforced disappearance, meager economic growth and questions over future energy policy.

Jorge Alvarez Maynez, a 38-year-old former member of congress who is trailing in third place, will close his campaign with a concert in Mexico City.