Obama chides China for campaign wedge

Romney said '47 per cent of Americans pay no income tax,' but that his role 'is not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives'. (AAP)

Romney said '47 per cent of Americans pay no income tax,' but that his role 'is not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives'. (AAP)

US President Barack Obama has lodged an unfair trade complaint against China, while Mitt Romney's campaign has hit a pothole.

US President Barack Obama has lodged an unfair trade complaint against China and immediately used it as a wedge against Republican challenger Mitt Romney, whose beleaguered campaign has hit another pothole.

Obama told voters in Ohio, where the auto industry is important, of his administration's new push for the World Trade Organisation to sanction China for subsidising exports of vehicles and auto parts, and costing American jobs.

Romney dismissed the move as a distraction, arguing American businesses and workers would know better.

It was Romney's own campaign, however, that preoccupied many Republican activists on Monday.

A video surfaced showing Romney telling wealthy donors that almost half of all Americans "believe they are victims" entitled to extensive government support.

"I'll never convince them they should take personal responsibility and care for their lives," he tells the donors.

In the video reported by Mother Jones magazine, Romney was referring to the 46 per cent of Americans who do not owe federal income taxes; he put the figure at 47 per cent in his videotaped remarks.

Many of those Americans pay other forms of taxes.

While many such households are poor, some families making $100,000 a year or more pay no federal income tax because of various deductions and credits.

At a hastily called news conference late in the day, Romney conceded the comments weren't "elegantly stated" and were spoken "off the cuff".

The Romney campaign said: "Mitt Romney wants to help all Americans struggling in the Obama economy".

Obama's campaign manager, Jim Messina, called Romney's comments "shocking".

The video surfaced as Republican activists have watched with growing concern as opinion polls suggest Obama has opened a small lead over Romney since the Republican and Democratic conventions last month.

In Ohio on Monday, Obama noted that he, unlike Romney, would raise taxes on households making more than $250,000 a year. Romney's platform, the president said, "doesn't add up".

"They say the most important thing we have to do is reduce the deficit," Obama said.

"Then the first thing they do is to spend trillions of dollars more on tax breaks for the wealthy."

In Cincinnati, Obama reiterated his claims that Bain Capital, the private equity firm Romney headed for years, helped companies shift US jobs to China.

"He made money investing in companies that uprooted from here and went to China," the president said.