ORLANDO, Florida (Reuters) - Senator Mel Martinez, a native Cuban and a former chairman of the Republican Party, stunned supporters on Friday by abruptly announcing he is resigning from Congress “to get on with my life.”

U.S. Senator Mel Martinez (R-FL) discusses his plans to resign alongside his daughter Helen (L) and wife Kitty (R) at a news conference at the Orlando International Airport in Orlando, Florida August 7, 2009. REUTERS/Scott Audette

Martinez, 62, who earlier said he would not run for a second Senate term next year, told a news conference in Orlando, Florida, that he is in good health, has no new job lined up, and was not resigning because of any personal problems.

“I know it will give for great punditry,” Martinez said. “People will speculate and sometimes the best answer is the simplest answer.”

He said he was resigning because after 12 years in Washington, “It’s time I return to Florida and my family.”

Asked why he did not finish the 17 months remaining in his term, Martinez said, “I think the governor will appoint a good person to take my place and it will give me a good chance to get on with my life.”

His resignation was unlikely to change the balance of power in the Democratic-led Senate since Florida Governor Charlie Crist is certain to name a fellow Republican to replace him.

Crist earlier announced he plans to run for the seat next year but said he would not appoint himself as Martinez’s replacement.

Martinez said he did not know who Crist would choose but he expected to return to Congress in early September to see his successor sworn in. He said he would remain active in Republican politics and joked that journalists would probably find him at a nearby lake feeding the pigeons.

Before being elected to the Senate in 2004, Martinez headed the U.S. Department of Housing and Urban Development in the administration of George W. Bush and served as mayor of Florida’s Orange County.

He stepped down in 2008 as chairman of the Republican Party after holding the post for about 10 months.

Martinez came to the United States from Cuba as a boy and used his post as a U.S. senator to speak out against the communist government of his homeland.

On Thursday, Martinez broke ranks with most Senate Republicans when the Democratic-led Senate confirmed Sonia Sotomayor as the first Hispanic on the U.S. Supreme Court. Martinez is the only Hispanic Senate Republican.

The Florida Democratic Party was quick to react to news of Martinez’s plans to resign.

Chairwoman Karen Thurman called on Crist “to appoint an independent caretaker” before an election can be held next year to fill Martinez’s seat.

“U.S. Senate seats should not be political footballs,” Thurman said in a statement.

“In 2010, every statewide office in Florida will be wide open with no incumbents running for re-election,” Thurman said. “Democrats are working to seize our historic opportunity.”

(Additional reporting by Thomas Ferraro in Washington)