Newt Gingrich hopes his runaway win in home state Georgia onSuper Tuesday can serve as a launchpad for a southern sweep that can get him right back into the Republican presidential race.

"Thank you Georgia! It is gratifying to win my home state so decisively to launch our March Momentum," the former House speaker tweeted immediately after US media networks announced his victory.

"In the morning, we are going on to Alabama, we are going on toMississippi, we are going on to Kansas, and that is just this week," he vowed in a victory speech at his Atlanta headquarters to cheering supporters.

According to exit polls, Gingrich took 45 percent of the Georgia vote, compared to 26 percent for former Massachusetts governor Mitt Romney, the favorite for the nomination, and 20 percent for ex-senator Rick Santorum.

It was only the second primary win so far for 68-year-old Gingrich. After his shock victory in South Carolina in January, he was outspent and steamrolled by the Romney juggernaut in Florida and his support plummeted.

But the victory in Georgia, where voters elected him to Congress for 20 years, could turn things around for the Republican Party's self-proclaimed philosopher king, an irascible showman seeking the ultimate redemption.

Four Republican candidates are still fighting for the right to take on President Barack Obama, a Democrat, in the November 6 general election.

Delegates are awarded by each state in the complex Republican Party nominating process, with one candidate needing to reach 1,144 delegates to declare victory.

In terms of delegates, Georgia was the biggest prize on Super Tuesday with 76 up for grabs, even though more attention was being paid to Ohio, where Santorum and Romney were locked in a tight contest that was too close to call.

Gingrich will now go all-out for victories in Kansas on Saturday, and in the conservative southern states of Alabama and Mississippi next Tuesday.

Romney, a multimillionaire businessman from the liberal state of Massachusetts, is expected to struggle in the south.

"This is awesome, I knew it, Georgia knows very well how smart Gingrich is and (about) his skills to do something for the economy," Robyn Helpern, one of 400 supporters at the Newt 2012 Election Night Party in Atlanta, told AFP.

"I'm sure this victory will help him to win next week in Alabama, he's the best candidate!" the 47-year-old dental assistant said.

The success of Gingrich's Deep South strategy could depend on Santorum. If the former Pennsylvania senator loses momentum after Super Tuesday, Gingrich can again portray himself as the chief alternative to Romney.

There are many reasons Gingrich might fail to become president, but lacking big ideas won't be one of them: the Republican with an instantly recognizable square head is a restless thinker.

Where critics see hypocrisy in three marriages and marital affairs while preaching family values, supporters find redemption and say that Gingrich, who converted in 2009 to Catholicism, has atoned for his sins.

The former House speaker is nothing if not determined and he has already come back once in this race after being counted out, thanks to a moment in South Carolina that will live long in Republican campaign history.

Targeted with the first question of a high-stakes live debate in the heart of America's Bible Belt, Gingrich was asked to comment on the bombshell allegation from his ex-wife that he had once requested an open marriage.

With his presidential hopes hanging in the balance, Gingrich struck out at the "destructive, vicious, negative nature of much of the news media," saying it was "as close to despicable as anything I can imagine."

The stunning counter-attack, which played brilliantly to the innate conservative distrust of the liberal media, transformed the former House speaker from villain to hero and recast his fortunes.

Emory University political scientist Alan Abramowitz said it is make-or-break time for Gingrich.

"He may have more hope if he wins in Alabama and Mississippi next week but every day seems more difficult."

In his Georgia victory speech, Gingrich warned those who count him out that he would keep plodding on.

"There are lots of bunny rabbits that run through. I'm the tortoise, I just take one step at a time."