President Barack Obama said the state of the US union was "getting stronger," defending his policies by saying "we've come too far to turn back now."

"As long as I'm president, I will work with anyone in this chamber to build on this momentum," Obama said in his State of the Union address, recalling tough partisan battles that have plagued his presidency.

"The state of our Union is getting stronger," Obama vowed in his annual speech to both chambers of Congress.

The US leader said he intended "to fight obstruction with action," and "oppose any effort to return to the very same policies that brought on this economic crisis in the first place."

"We will not go back to an economy weakened by outsourcing, bad debt, and phony financial profits," Obama said.

He entered the White House in 2009 amid the worst economic downturn in decades, and pledged in his speech Tuesday to rebuild the US economy with an emphasis "on American manufacturing, American energy, skills for American workers, and a renewal of American values"

Obama hailed the end of the war in Iraq and the death of Osama bin Laden, as he trumpeted his credentials as commander-in-chief.

"For the first time, there are no Americans fighting in Iraq. For the first time, in two decades, Osama bin Laden is not a threat to this country," the president said, in a speech to US lawmakers which effectively launches his campaign for re-election in November.

Praising "this generation of heroes" which has "made the United States safer and more respected around the world," Obama won his first standing ovation of the night from some of the gathered lawmakers.

"Most of Al-Qaeda's top lieutenants have been defeated. The Taliban's momentum has been broken, and some troops in Afghanistan have begun to come home," he said.

Addressing rows of military men in uniform from his top joint chiefs of staff, Obama praised the achievements as "a testament to the courage, selflessness, and teamwork of America's Armed Forces."

"At a time when too many of our institutions have let us down, they exceed all expectations. They're not consumed with personal ambition. They don't obsess over their differences. They focus on the mission at hand. They work together."