Could Mitt Romney be president in 2016?

Washington - Americans may not be through with Mitt Romney after all.

The two-time Republican presidential candidate has repeatedly stressed over the past year that he is not interested in a third shot at the White House.

But an Iowa poll released on Wednesday suggests that Romney, the former Massachusetts governor who lost to President Barack Obama in 2012, would be the party's odds-on favourite if he threw his hat in the ring for 2016.

The survey of Iowa Republican voters conducted by Suffolk University and USA Today showed that if Romney was added to the pool of potential 2016 Republican contenders, 35% of respondents would place him first in the Iowa caucuses, the political contest that kicks off the primary calendar.

Arkansas ex-governor Mike Huckabee came in a distant second, at just 9%, with New Jersey Governor Chris Christie trailing at 6.5% and former senator Rick Santorum at 6%.

Senators Ted Cruz and Rand Paul each earned 5%, while the remaining field was in the low single digits.

Only 170 likely caucus voters took part in that section of the poll, but it nevertheless fuels the frenzy over who will top the Republican ticket.

Just Tuesday on the Hugh Hewitt Show radio programme, Romney recalled his two previous losses and noted that "someone else has a better chance than I do" in 2016.

But he also left the door open. "You know, circumstances can change, but I'm just not going to let my head go there", Romney said.