Republican voters in the southeastern U.S. state of Florida are heading to the polls Tuesday in what is expected to be a pivotal contest in the race for the party's presidential nomination.

A recent survey of likely voters showed that multi-millionaire investor and former governor of Massachusetts Mitt Romney holds a 14-percent lead on his closest rival, former House speaker Newt Gingrich.

More than 600,000 Floridians also already have cast ballots in early voting leading up to Tuesday's primary, with polls showing most of those votes going for Romney.

Both candidates have campaigned hard in the state. Analysts expect the results to have a huge impact on who will face Democrat Barack Obama in the November presidential election.

Two other candidates are also on the ballot in Florida, former U.S. Senator Rick Santorum and Texas congressman Ron Paul, although poll show both far behind the front-runners.

Romney also needs a win in Florida to regain his momentum after losing to Gingrich by double-digits in the South Carolina primary January 21.

Gingrich lashed out at Romney on Monday, accusing him of being a liberal and running dishonest political ads. The former congressman says he expects a long campaign in the battle for the Republican presidential nomination.

Speaking after a church service Sunday near the city of Tampa, Gingrich called Romney a “pro-abortion, pro-gun control, pro-tax increase moderate from Massachusetts.”

Romney has said that Gingrich is making excuses for his debate performances, and blasted Gingrich for being found guilty of ethics violations that forced him to resign as House speaker.