Warning the nation cannot long prosper "when it favours only the prosperous," the new president told the cheering crowds on Tuesday that "everywhere we look, there is work to be done.

"Our economy is badly weakened, a consequence of greed and irresponsibility on the part of some, but also our collective failure to make hard choices and prepare the nation for a new age," Obama said in his inaugural speech.

"Homes have been lost; jobs shed; businesses shuttered. Our health care is too costly; our schools fail too many; and each day brings further evidence that the ways we use energy strengthen our adversaries and threaten our planet."

The way forward, the new president pledged, was to act now.

"The state of the economy calls for action, bold and swift, and we will act -- not only to create new jobs, but to lay a new foundation for growth.

"We will build the roads and bridges, the electric grids and digital lines that feed our commerce and bind us together."

In the run-up to his inauguration, Obama warned of a "tough year" ahead and a recession that will linger for much longer unless Congress takes "dramatic" action on his mammoth stimulus plan.