WASHINGTON (Reuters) - Likely Republican presidential contender Jeb Bush, who was popular among Spanish-speaking voters while Florida governor, marked himself as "Hispanic" on a 2009 voter registration application, The New York Times reported on Monday.

The newspaper posted a fuzzy copy of the form, which it said it obtained from the Miami-Dade County Elections Department. The circle marked "Hispanic" was checked. The next circle said "White, not Hispanic" and was not checked.

"My mistake! Don't think I've fooled anyone!" Bush wrote on Twitter on Monday, responding to a message from his son calling him an "honorary" Latino.

A Bush spokeswoman said it was unclear how the error was made. "The governor's family certainly got a good laugh out of it," spokeswoman Kristy Campbell said. "He is not Hispanic."

Carolina Lopez, a spokeswoman for the county elections department, did not immediately return calls from Reuters.

The brother of former President George W. Bush and son of former President George H.W. Bush, Bush is exploring a presidential bid and is considered a front runner in the crowded field of possible Republican candidates. He was born in Texas.

Bush, who speaks fluent Spanish and whose wife, Columba, is Mexican-born, had widespread support among Hispanic voters during his two terms as Florida governor.

His stance on immigration has been at odds with the views of many in his party, including when he said last year that illegal immigrants who come to the United States to provide for their families are not committing a felony but an "act of love."

(Reporting by David Adams in Miami and Steve Holland in Washington; Writing by Doina Chiacu; Editing by Lisa Lambert and Leslie Adler)