Republican presidential candidate Mitt Romney, seeking to salvage his bid for his party's nomination, stressed his local roots and business credentials as he campaigned across Michigan ahead of the state's Tuesday primary.

Romney, a wealthy businessman and former Massachusetts governor, sank millions of dollars into the first contests in Iowa and New Hampshire, but came in a disappointing second in both states, behind Baptist preacher and former Arkansas governor Mike Huckabee and Arizona Senator John McCain respectively.

Polls showed Romney and McCain in a close race in the Midwestern state that has been hit hard by an ailing US auto industry, with an average of several polls in the state showing the candidates less than 1 percentage point apart. Huckabee was polling third.

Romney grew up in Michigan, where his father led a now-defunct auto manufacturer and served as governor, and he hopes to translate his home field advantage into a win that would further shake up the unsettled Republican field.

In campaign stops Monday, he stressed his business credentials as head of a venture capitalist firm and president of the Salt Lake City Olympic committee and said he would work to turn around the state's economy.

He evoked Detroit's former manufacturing prowess, now gutted by international competition that has left the state with the highest unemployment rate in the country - 7.4 per cent in November, according to the federal Bureau of Labor Statistics.

"I want to bring Michigan back," Romney said. "I'm not willing to sit back and say, 'Too bad for Michigan. Too bad for the car industry. Too bad for the people who've lost their jobs; they're gone forever.'"

McCain, a vocal supporter of the Iraq war who long supported an increase in the number of troops, came back to win last week's contest in New Hampshire. National polls now show him leading the Republican field after his campaign had been declared dead by analysts over the summer.

The Vietnam war veteran and former prisoner of war won the Michigan primary in 2000 when campaigning against George W Bush, who went on to defeat him for the Republican nomination.

At a campaign event Monday, he touted his plan to revive the auto industry through investments in green technology and other advances.

"I will herald a new day for Michigan, and I will do everything I can to make sure the heartland of America, the state that saved the world during World War II will again resume its rightful place in our economy and in our nation and in the world," said McCain, who was to attend the Detroit auto show later in the day.

Romney was also to visit the event.

Leading Democratic contenders have shunned Michigan altogether after the state defied national party leaders and moved its primary forward in the schedule of state-by-state nominating contests. States across the country have rushed to bump up their primary dates as far as the parties would allow, in order to have a greater say in the decision making process.

The Democratic National Committee stripped the state of all its delegates to its August convention, where the party's candidate will be officially named ahead of November 4 general elections.

The top Democrats have not campaigned in Michigan and will instead focus on a debate in Las Vegas Tuesday ahead of the Nevada primary on Saturday.

Hillary Clinton was the only leading Democrat to even appear on Michigan's ballot, and long-shot Dennis Kucinich was the only member of the party to hold campaign events there Monday.

The Republican National Committee stripped Michigan of just half its delegates to its convention in September.