By Sam Youngman

WOLFEBORO, New Hampshire (Reuters) - A who's who of Republican leaders, including three thought to be possible running mates for Republican presidential candidate Mitt Romney, will kick off the party's convention this month.

Romney will formally accept the Republican nomination on August 30, after former Secretary of State Condoleezza Rice, Senator John McCain, South Carolina Governor Nikki Haley and 2008 Republican presidential candidate Mike Huckabee address the convention.

Rice, Haley and New Mexico Governor Susana Martinez were mentioned in recent weeks as possible running mates.

Giving a nod to the critical state of Ohio, the state's Governor John Kasich rounds out the early list of convention speakers.

Republican officials confirmed the headline speakers Sunday night after they were first reported by The Tampa Bay Times.

Three Republicans thought to be at the top of Romney's shortlist of possible running mates - Ohio Congressman Rob Portman, former Minnesota Governor Tim Pawlenty and Congressman Paul Ryan - were conspicuously absent from the early list of speakers.

Romney has continued to play coy in recent days, telling reporters last week "I got nothing for you" when asked about his decision.

Rice was the most recent hot pick to make the rounds after a report on The Drudge Report last month said she was on Romney's shortlist.

Florida Governor Rick Scott will kick off the event in Tampa on August 27.

(Reporting By Sam Youngman; Editing by Stacey Joyce)