WASHINGTON, USA (AP) — Fresh signs of a national housing rebound and growing support in public opinion polls boosted President Barack Obama's bid for a new term in the White House on Wednesday as Republican rival Mitt Romney struggled to quell his video controversy.

The challenger's attempts to get his campaign back on track ran into new difficulty in the form of criticism from rank-and-file Republicans concerned about their own election prospects in the fall.

"I have a very different view of the world," said appointed Sen. Dean Heller of Nevada, taking issue with Romney's dismissive comments about the 47 per cent of all Americans who pay no income taxes. Separately, Senate GOP leaders avoided answering questions about their presidential candidate at a news conference in the Capitol.

After days of virtually non-stop political damage control on issues foreign and domestic, Romney told an audience at an Atlanta fundraiser: "The question of this campaign is not who cares about the poor and the middle class. I do. He (Obama) does. The question is who can help the poor and the middle class. I can. He can't."

The former Massachusetts governor spoke about 48 hours after a video emerged that showed him telling donors last May that as a candidate for the White House, "my job is not to worry about" the millions of Americans who don't earn enough to pay income taxes.

Obama spent the day in the White House, a rarity in a race with less than seven weeks yet to run. He invited democracy advocate Aung San Suu Kyi of Myanmar to the Oval Office, a chat between two Nobel Peace Prize winners.

Romney raised campaign cash in Georgia in advance of an evening appearance in battleground Florida, his first before a public audience since the emergence of the videotape. Under pressure from fellow Republicans to campaign more extensively, he was considering adding at least one appearance to a light weekend schedule, officials said.

In a campaign dominated all year by the sluggish economy, the government said construction of single-family homes jumped to the highest rate in more than two years. Separately, the National Association of Realtors reported that home sales rose last month to the highest level since May 2010.