Media playback is unsupported on your device Media caption Voters in New Hampshire give their views on the race for the White House

Polls are closing in New Hampshire where voters have been choosing the Republican candidate they want to see take on President Obama in November.

Front-runner Mitt Romney faced last-minute attacks from rivals attempting to brand him a heartless job cutter.

But the latest opinion polls suggest he will easily win the first primary of the Republican nomination process.

Jon Huntsman, who has staked everything on New Hampshire, is battling with Ron Paul for runner-up, polls suggest.

Primaries and caucuses will take place in every US state over the next few months to pick a Republican nominee before the eventual winner is crowned at the party convention in August.

A poor showing could force former Utah Governor Huntsman, who was the Obama administration's first ambassador to China, to drop out of the race.

Rick Santorum - who ran former Massachusetts Governor Romney a close second in last week's Iowa caucuses - and Newt Gingrich are battling it out for right-wing conservative votes.

Key facts: New Hampshire New Hampshire enacted a law in 1977 to ensure it would be the first primary in the nation

Voter turnout in the state ranks among the highest in national elections

Since 1972, the eventual Republican nominee has always won either New Hampshire or Iowa

The state's primary allows for unregistered voters to vote in either party's primary

In 2008, 34% of New Hampshire Republican primary voters were independent Rick Santorum, cultural warrior Conservatives unsure on Romney

Former Pennsylvania Senator Santorum and former House Speaker Gingrich have one eye on a primary later this month in staunchly Republican South Carolina. Their fellow conservative Texas Governor Rick Perry is already in that state campaigning.

Most polls across New Hampshire, which has a reputation for bucking the national trend, have been open since 07:00 (12:00 GMT) are expected to close at 19:00 local time, with the remainder closing at 20:00 local time.

Election officials are predicting a near record turn-out despite a slow but steady start to the day in some parts of the state, according to New Hampshire's Union-Leader newspaper. Analysts estimate about 250,000 Republican voters will turn out.

A Reuters/Ipsos opinion poll on Tuesday suggested Mr Romney was far ahead of his Republican rivals nationally, with 30% support.

It also indicated Mr Romney was trailing Democratic President Obama by five percentage points were he to challenge him for the White House now.

If Mr Romney triumphs in Tuesday's primary it would be the first time a non-incumbent candidate had won the first two nominating contests in a Republican race for the White House.

But his rivals have sought to exploit an off-the-cuff remark he made in New Hampshire on the eve of the primary.

You have to be very wary when politicians are being accused of making "gaffes". They are often nothing of the sort, a mountain made out of a molehill by reporters desperate for a story. The idea of a politician saying he likes firing people, when so many live in fear of losing their jobs, is toxic. It puts him on the wrong side of the "them and us" divide. But it is quite clear Romney's remarks were ripped out of context. He was talking about changing health insurance companies when they are not doing a good job. Read more of Mark's thoughts

"I like being able to fire people who provide services to me," said Mr Romney, who was discussing how he wanted consumers to pick and choose private health insurers.

Mr Romney has also come under attack over his leadership of a private equity firm, Bain Capital.

He has claimed he helped to create more than 100,000 jobs during his time at Bain Capital.

The former governor casts himself as a job creator who can turn around the US economy at a time when the unemployment rate is 8.5%.

President Obama is seeking re-election amid voter concern at the pace of economic recovery from the recession that started in 2007 during the White House tenure of George W Bush and ended in 2009.