Mitt Romney on Wednesday cemented his standing as the Republican front-runner for the White House by sweeping to victory in the New Hampshire primary, turning back a ferocious assault from rivals.

Romney, the former Massachusetts Governor, won the New Hampshire primary by a double digit margin. His victory came on the heels of his win in the Iowa caucus last week by just eight votes in a nail biting finish.

The leading Republican candidate received a whopping 40 per cent of the total votes polled in the New Hampshire Republican primary.

Texas Congressman Ron Paul finished second, way behind with 23 per cent and former Utah Governor Jon Huntsman, who also served as the US Ambassador to China during first two years of the Obama Administration, was placed a poor third.

Rick Santorum, who lost the Iowa caucus by just eight votes, polled less than 10 per cent of votes and so did Newt Gingrich, former Speaker US House of Representatives, making Romney the hot favourite to take on the incumbent President Barack Obama in November elections.

This is for the first time that a Republican candidate has won both the Iowa Caucus and New Hampshire primary.

From New Hampshire, all the Republican candidates move to South Carolina, which is expected to experience a fierce battle among these six Republican presidential aspirants.

With two wins, Romney is ahead of others as he became the first Republican, other than a sitting president, to win both Iowa and New Hampshire. "We made history," Romney said in his victory speech in Manchester.

"Romney's convincing victory here, in a state he had long expected to dominate, substantially narrows the prospects of other Republican candidates as the contest moves into larger states, where Romney's financial and organizational strengths are likely to increase his advantages," The Wall Street Journal reported.

In its lead story, The New York Times said Romney swept to victory in the New Hampshire primary, turning back a ferocious assault from rivals who sought to disqualify him in the eyes of conservatives, in a contest that failed to anoint a strong opponent to slow his march to the Republican nomination.

''Romney, who struggled in the final hours of the campaign here to ward off attacks from rivals portraying him as an elitist who killed jobs during his high-flying days at a corporate takeover firm, delivered a pointed message to his fellow Republican candidates.''

''He warned them not to play into President Obama's hands by trying to destroy his candidacy," the daily said. The Washington Post said in recent days, the tone of the campaign, particularly in the attacks on Romney, had taken a sharply negative turn.

"Romney's rivals have focused not on their policy differences with him, which by and large are relatively small, but on his character and fitness to lead the country," the daily said.

According to Fox News, New Hampshire performance puts Romney's campaign in strong position going into South Carolina which goes to primary on January 21.

"Romney's win in New Hampshire, coupled with his victory in the very different state of Iowa, cements his status as the clear frontrunner for the GOP presidential nomination - albeit one about whom many Republicans have yet to embrace, as evidenced by national polls showing him unable to win more than 30 percent support," CBS news said.