AMES, Iowa — Republican White House candidate Mitt Romney wooed Iowa voters with a warning that President Barack Obama's policies "are making us more and more like Europe."

"I don't think Europe is working in Europe. I don't want Europe here. Ours was formed as an opportunity nation," Romney said at an evening rally in the cavernous headquarters of a construction company.

Congressional Republicans have leveled similar accusations since Obama took office in January 2009, warning that rising US debt threatens to swamp the weak US economy and pointing to crisis-hit Greece and Italy as cautionary tales.

And Romney himself has deliberately echoed a famous election slogan used by British prime minister Margaret Thatcher: "Labor isn't working."

"The president's policies of making us more like Europe, they're not working," he said in Ames as he pursued a bus tour across Iowa, where Republicans will cast the first votes of the Republican presidential nominating contest on Tuesday.

"I want to keep America, America," said the former Massachusetts governor, who accuses Obama of getting the government overly involved in the daily workings of the economy.

Romney 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 -- though doubts remain among primary voters.

"I'm still shopping. I want anybody but Paul or Obama," retired railroad worker Craig Wearmouth, 64, told AFP at the rally, referring to veteran Texas Representative Ron Paul, whose libertarian philosophy rankles core Republicans.

Wearmouth said he preferred Representative Michele Bachmann, who lags far behind Romney in recent public opinion polls, "I don't know if we can get her elected, so I've got to look elsewhere."

Asked about Romney, Wearmouth said "I'm really worried about how sincere he is" about repealing Obama's overhaul of US health care and enacting tougher measures to curb undocumented immigrants.

"I don't care what he says. I want to know what he's going to do," the rail worker added.

Romney's vast campaign warchest and high-profile endorsements have long fed his reputation as the candidate to beat -- yet he has not been able to swell his support above 30 percent of Republican voters.

Holding her eight-month-old daughter in her arms, Leah Fonua, 26, said she was also "still shopping around" for a candidate "who's going to help with public health, people in poverty and our economy."