His supporters make thousands of campaign calls and blanketFlorida with signs as they dream of Newt Gingrich in the White House, but for many in his Republican Party such a scenario would be nothing short of a nightmare.

After the former House speaker's shock win in South Carolina, morale soared at Newt headquarters in this sprawling city four days ahead of a crucial Florida primary that could put Gingrich -- or his main rival Mitt Romney -- in the driver's seat as they chase the Republican presidential nomination.

Dozens of volunteers swarmed the ground floor of a small red brick house as they carried out campaign duties for the most controversial conservative in the race to see who will go head to head with President Barack Obama in November.

"We went from 50 volunteers to about 250," said Gingrich's local campaign chairman Bert Ralston. "We knew it was coming, but it's fantastic."

They put up campaign placards, distribute "Newt 2012" stickers, strategize, and of course make calls to prospective voters seeking their support for a candidate whose rivals deride him as bombastic and "erratic."

The calls are simple and direct, with volunteers reading from a script: "Newt Gingrich is the only candidate with the experience and vision to... rebuild the America we love. I hope we can count on your support."

An 11-year-old boy on Tuesday made some 75 campaign calls for Gingrich, volunteer John Libby said.

Retired history professor Don Rawlins, energized by the ultra-conservative Tea Party movement, is a fervent Gingrich supporter who helped post Newt signs at a campaign rally on the University of North Florida campus.

"The country is under water, the house is flooded, and we want the best plumber, regardless of the flaws he may have," Rawlins told AFP.

Gingrich has been castigated by social conservatives for his extramarital affairs that led to two messy divorces, and his toxic reign as House speaker in the 1990s has received fresh scrutiny.

Recently, conservative pundits have been among his most ardent critics, saying that while Romney might be too moderate to be a true conservative, the former Massachusetts governor and millionaire investor would be a stronger candidate against Obama in November.

But Rawlins said he is looking beyond Gingrich's shortcomings and occasional pie-in-the-sky ideas, including claims he will establish a permanent moon base by 2020 if elected.

"He is straightforward, he discusses the things that matter, he has the experience," Rawlins said.

Leaette Vollmar, who traveled 560 miles (900 kilometers) from Tennessee with her niece to attend the Gingrich rally at the University of North Florida, was equally succinct.

"He is bright, he knows how to get the job done, he won't flipflop," she said, belittling Romney for having changed his stance on issues such as health care and abortion.

"He (Romney) is from Massachusetts, that tells it all," Vollmar said of the historically liberal state.

In Florida Gingrich has often compared himself to conservative icon Ronald Reagan, the 1980s Republican president. He has hoped to capitalize on an electorate frustrated by high unemployment and a collapsed housing market, and who he hopes recognizes the anti-establishment bent to his campaign speeches.

But after a bump, Gingrich is suffering a post-Carolina slump, with a new poll Friday showing Romney has opened up a nine-point lead among likely Republican voters in Florida. An aggregate of polls shows Romney at 38.7 percent compared to Gingrich at 31.5 percent.

While Gingrich's grass roots support is impressive, some Republicans no longer hide their discomfort with the renaissance of a man who left Congress in 1999 under a cloud after a House ethics committee penalized him $300,000 in the first-ever reprimand of a sitting speaker.

On Thursday, the establishment unleashed 89-year-old Bob Dole, the Republican presidential nominee in 1996, who publicly voiced the fears that many were whispering about Newt.

"It is now time to take a stand before it is too late," Dole said in an open letter.

"If Gingrich is the nominee it will have an adverse impact on Republican candidates running for county, state and federal offices,' he said.

"Hardly anyone who served with Newt in Congress has endorsed him and that fact speaks for itself," he added.

"He was a one-man-band who rarely took advice. It was his way or the highway."

Republican Representative Peter King told Washington website Politico that a Gingrich nomination would "make it difficult" to keep a Republican majority in the House. "There is just real concern."