TEGUCIGALPA (Reuters) - Honduran presidential candidate Xiomara Castro, the wife of deposed former President Manuel Zelaya, is leading the race to become the next head of the Central American country, according to a poll released on Tuesday.

Political newcomer Castro, the Liberty and Refoundation Party candidate who established her reputation while fighting for her husband's right to rule after his 2009 military-led ouster, leads with 25 percent of those questioned saying they would vote for her, according to the CID Gallup poll.

Just 23 percent said they would vote for National Party candidate Juan Hernandez who, the pollster said, "is being affected by the ongoing divisions in his party."

Nonetheless, 33 percent of the 1,256 people surveyed for the poll said they supported Hernandez's National Party, while only 21 percent opted for the Liberty and Refoundation Party (LIBRE), with a similar amount picking the third-placed Liberal Party.

The poll has a 2-percentage-point margin of error, according to La Prensa newspaper that published the survey.

Castro and her party, a coalition of leftist politicians, unions, agrarian and indigenous groups, vow to call a referendum to rewrite the constitution if they win - an act that previously set in motion the coup that ended her husband's presidency.

Zelaya was deposed in a 2009 military coup after his opponents said he was trying to change the constitution to remain in power.

Last week, Honduras' Congress approved an impeachment tool to remove top-ranking officials from office and avoid crises like the 2009 coup.

Among the nine candidates vying to become Honduras' next president is retired General Romeo Vasquez, who led the coup against Zelaya and who leads the Patriotic Alliance, a party mainly comprised of retired soldiers. He was not in the poll.

The presidential elections will take place in November, with the victor assuming office in January 2014.

(Reporting by Gustavo Palencia; Writing by Gabriel Stargardter; Editing by Philip Barbara)