WASHINGTON - US President Barack Obama's job approval ratings plunged to a new low ahead of his major economic speech on Thursday, with widespread discontent among Americans over his handling of the economy and jobs, according to a spate of polls released on Tuesday.

An NBC News/Wall Street Journal poll of 1,000 US adults showed Obama's overall job approval rating at a low of 44 percent, down 3 percentage points since July, while his handling of the economy stands at 37 percent.

A Democratic pollster who helped conduct the survey said the poor results, which contain a 3.1 percentage-point margin of error, suggest Obama is no longer favored to win re-election in 2012.

An ABC News/Washington Post poll of US adults showed that six in 10 Americans rate the president's job on the economy and jobs negatively, while one in three say they are now worse off financially since Obama entered the White House. It has a 3.5 percentage point margin of error.

A third poll of 1,000 likely voters by Washington-based Politico and George Washington University found that 72 percent of voters believe the country is either strongly or somewhat headed in the wrong direction, a jump of 12 percent since last May. That survey's results have a 3.1 percentage point error margin.

The polling, conducted last week, offers grim news for the president after a summer spent wrangling with Republicans in Congress over the debt ceiling and the budget in a rancorous debate that ended with Standard and Poor's unprecedented downgrade of the US triple-A credit rating.

The polls also come three days ahead of his widely anticipated presidential speech to Congress, in which Obama is expected to confront Republican resistance to his agenda for creating jobs and spurring economic growth.

The package is expected to include projects for rebuilding roads, bridges and other infrastructure across the country, an approach Republicans who control the House of Representatives reject as wasteful spending.

New job figures, showing zero US employment growth in August and a national jobless rate stuck at 9.1 percent, have stoked fears the US economy could slide back into recession.

Obama's ability to reignite the economy could determine whether he keeps his own job in the White House after 2012.

The NBC/Wall Street Journal poll showed the president leading Republican front-runner Rick Perry, the Texas governor, by 47 percent to 42 percent and former Massachusetts Governor Mitt Romney by 46 percent to 45 percent.

But for the first time in that poll, Obama lost out to a generic Republican candidate by 44 percent to 40 percent, which could suggest a serious campaign obstacle given the bleak economic picture.

"Obama is no longer the favorite to win re-election," said Democratic pollster Peter Hart, who conducted the NBC/Wall Street Journal survey with Republican pollster Bill McInturff.