US President Barack Obama admitted Thursday he second-guesses himself all the time and makes frequent mistakes but that experience had made him a better leader.

Obama defended his economic policies vigorously in an interview with ABC News and argued that America would have been much worse off had it not been for the steps he had taken to tackle the deepest recession in decades.

"I second-guess myself constantly ... I make a mistake, you know, every hour, every day," Obama said, laughing, in an interview conducted in Las Vegas with ABC News.

"There're always things that you're learning in the job. And I have no doubt that I'm a better president now than the day I took office just because you get more experience.

"But when you look at the broad outlines of what we did, had it not been for the steps we took, our economy would be profoundly weaker than we are right now," Obama said.

Republicans, including some who want to take on Obama in November's election, constantly assail his economic policies and competency, and political opponents have often accused him of hubristic behavior.

US presidents face a political minefield when they are asked about things, in hindsight, they would have done differently.

If they admit to errors, they risk being seen as indecisive but if they say they did nothing wrong, they can come across as isolated and stubborn.

On one famous occasion, former president George W. Bush was asked to name some mistakes he had made in office -- but he could not name a specific error off the top of his head -- and earned a torrent of media ridicule.