Republican White House hopeful Mitt Romney, bolstered by a new poll confirming his frontrunner status, ripped President Barack Obama on Friday over his year-end Hawaii vacation.

Hunting for a win in Iowa's first-in-the-nation January 3 nominating caucus, Romney used the embattled Democratic incumbent's annual family trip to his native state to paint him as out of touch with Americans' economic suffering.

"He's in Hawaii right now. We're out in the cold and the rain and the wind because we care about America, he's out there. He just finished his 90th round of golf," the former Massachusetts governor told a rowdy crowd.

"We've got 25 million Americans that are out of work, or have stopped looking for work, or are underemployed, home values have come down," he told supporters who braved an icy drizzle and a near-freezing wind at the morning event.

"Do you want more of Barack Obama?" he called out, drawing a loud "no" from the assembled Iowans and a grin from New Jersey Governor Chris Christie, who is popular with conservatives and was here campaigning for him.

Obama, currently taking his annual Christmas and New Year vacation with his family in his native state of Hawaii, faces an uphill fight for re-election, weighed down by the sour economy and historically high unemployment.

Romney, who hopes to take on the president in the November 2012 elections, pointed out a sign at the rally that read "In Obama We Trusted, Now Our Economy Is Busted" and declared: "You got it right, brother."

The former governor, whose vast campaign warchest and high-profile endorsements have fed an image as the candidate to beat for the Republican nomination, said Obama was trying to convince voters that "it could be worse."

"That goes down with Marie Antoinette, 'let them eat cake,'" he said, referring to remarks popularly believed to have been uttered by the Austrian-born French queen ultimately beheaded during France's revolution when she was told that the people lacked bread.

The former governor got good news earlier from a new NBC News/Marist poll that confirmed his frontrunner status in Iowa, with 23 percent of likely Republican caucus-goers saying they backed him.

Representative Ron Paul was second at 21 percent, followed by former senator Rick Santorum at 15 percent and Texas Governor Rick Perry at 14 percent, the telephone poll of 425 people on Tuesday and Wednesday indicated.

Lagging behind were former House of Representatives speaker Newt Gingrich at 13 percent, Minnesota congresswoman Michele Bachmann at six percent and former Utah Governor Jon Huntsman at two percent. Seven percent were undecided.

At a question-and-answer session with Iowans, Gingrich pledged his support for alternatives to fossil fuels, saying: "I would like us to become so energy independent that no American president ever again bows to a Saudi king."

He also knocked Romney, saying "I'm a more coherent conservative," and said that "all foreign aid ought to be on the table" for possible cuts as Washington looks to rein in its galloping debt.

Maura Kenworthy, 35, told AFP at the Romney rally that she voted for Obama in 2008 and felt sympathy for the embattled president -- "I don't envy his job" -- but will not support him next year "unless something drastically changes."

Romney hopes a first- or second-place finish here, coupled with a win in New Hampshire a week later, could help him steamroll his way to the nomination.

But while he has one of the best-oiled campaign machines in the crowded Republican field and has fended off successive candidates seen as more conservative than he is, doubts remain among rank-and-file conservatives.

"I'm really worried about how sincere he is" about repealing Obama's historic overhaul of US health care and cracking down on undocumented immigration, retired railroad worker Craig Wearmouth, 64, said at a Romney rally on Thursday.

Romney has the backing of much of the Republican establishment -- yet he has not been able to swell his support above 30 percent of Republican voters.

Unpredictable Iowa -- where unemployment is well below the national average -- is also an unreliable predictor of presidential fortunes: Senator John McCain, the eventual nominee in 2008, came in fourth that year.