KNOXVILLE, Iowa (AP) — The economy needs help and fast, Hillary Rodham Clinton declared Monday, claiming the experience for the job and saying the nation can't afford to break in a newcomer.

In speech excerpts provided by the Clinton campaign, the New York senator suggested Democratic rival Barack Obama and other candidates lack the experience necessary to address the nation's fiscal challenges.

''There is one job we can't afford on-the-job training for — our next president. That could be the costliest job training in history,'' Clinton said. ''Every day spent learning the ropes is another day of rising costs, mounting deficits and growing anxiety for our families. And they cannot afford to keep waiting.''

Clinton was to deliver the speech on the first day of a two-day visit to Iowa, the first voting state. Polls show her locked in a tight race with first-term Illinois Sen. Obama and one-term former North Carolina Sen. John Edwards just over six weeks before the state holds its caucuses Jan. 3.

For months, Clinton has hinted that Obama, less than three years into his first term, lacks the preparation to deal with U.S. foreign policy challenges. In Monday's address, she suggested the nation's budget deficit, income inequality and lack of comprehensive health coverage also required a more experienced steward.

''We need a president who understands the magnitude and complexity of the challenges we face and has the strength and experience to address them from day one,'' she said.

The speech also tackled the issue of Social security.

In recent weeks, Clinton and Obama have traded barbs over the retirement program for seniors, which is forecast to run out of money around 2041 Presently, the first $97,500 in individual income is subject to the Social Security tax — a level Obama has said must be increased in order to keep the program solvent.