WASHINGTON (AFP) - He may have lost the 2012 United States presidential election, but one-time Republican nominee Mitt Romney will take centre stage next month at a key conservative policy conference, organisers said on Wednesday.

Mr Romney's speech at the Conservative Political Action Conference, which as the nation's largest gathering of conservative leaders and activists attracts thousands of guests, will be his first major public appearance since his loss to President Barack Obama last November.

"We look forward to hearing governor Romney's comments on the current state of affairs in America and the world, and his perspective on the future of the conservative movement," chairman Al Cardenas of the American Conservative Union, the CPAC organizer, said in a statement regarding the March 14 to 16 event.

Mr Romney was also quoted, saying he looked forward to offering a "thank you to the many friends and supporters who were instrumental in helping my campaign."

Mr Romney is no stranger to CPAC.

He used his speech at the 2008 event to announce he was dropping out of the Republican primary race, eventually won by John McCain who lost to Obama in the general election.

And in 2012 as a candidate once again, he appeared at CPAC to defend what he called his "severely conservative" values, a comment seized on by conservatives who felt he was not far enough to the right, and Democrats who tarred him as a politician who flip-flopped on issues such as health care and abortion.

Mr Romney, a former governor of Massachusetts, has been laying low since his defeat, popping up occasionally in photographs on social media sites that apparently depict him shopping or filling his car at the gas station.

When Senator John Kerry of Massachusetts left Congress to become secretary of state last month, it opened up a race in his home state to fill his seat.

Speculation swirled that Mr Romney's oldest son Tagg might throw his hat in the ring, but he quickly ruled it out.

Mr Mitt Romney's wife Ann, a fixture on his presidential campaign, also has been mentioned as a possible Senate candidate but she has not addressed the issue publicly, and a Romney confidante was quoted by the Boston Herald as saying "the timing is not great" for her as a candidate.