House Republicans supporting former Massachusetts Gov. Mitt Romney (R) will hold a Capitol Hill press event today to unveil new additions to their team — additions that move him ahead of Sen. John McCain (Ariz.) in public Congressional endorsements as the battle for Member support continues at a torrid pace between two of the leading GOP presidential hopefuls.

McCain, viewed as the frontrunner for the GOP nod next year, named his six-person House whip team last week and also announced the support of three Cuban-American Members.

Members of Romney’s team will appear at an afternoon news conference at the Capitol Hill Club. About half of Romney’s Capitol Hill supporters previously have been announced.

Rep. Jim McCrery (R-La.), who is Romney’s liaison in the House chamber, said the Republicans now on board constitute the former governor’s initial whip team.

“We’ll be utilizing these 22 Members to bolster support for Romney here on Capitol Hill,” he said.

Among the endorsements to be announced today are those of Reps. Rodney Alexander (La.), John Linder (Ga.), Ralph Regula (Ohio), Bill Shuster (Pa.) and Mike Simpson (Idaho).

Last week, McCain unveiled his House whip team and also announced the support of Florida GOP Reps. Ileana Ros-Lehtinen, Lincoln Diaz-Balart and Mario Diaz-Balart. His campaign is expected to announce the addition of Rep. Ric Keller (Fla.) today. Keller’s Orlando-based district is sandwiched between those of Romney supporters — Reps. Ginny Brown-Waite and Tom Feeney.

Yesterday, McCain announced the support of two Michigan state lawmakers and named members of his Florida finance team.

The dueling for Member endorsements between Romney and McCain comes as former New York Mayor Rudy Giuliani formally stepped into the Republican White House fray Monday by filing a statement of candidacy with the Federal Election Commission.

Giuliani has a quartet of Members supporting his candidacy but has yet to show he’s been as aggressive as his two principal rivals in reaching out to Capitol Hill.

Romney’s list thus far is a mix of the party’s rising stars in the House — such as Reps. Marsha Blackburn (Tenn.), Mike Rogers (Ala.) and Feeney — and established veterans such as Regula, Rep. Hal Rogers (Ky.) and former Speaker Dennis Hastert (Ill.).

McCain, understandably, has more support within the Senate than Romney does and his House team also includes many veteran lawmakers — albeit most who are not particularly known as conservative firebrands.

While about half of Romney’s team thus far is made up of social conservatives from Southern states, McCrery said that was more a function of the Members who were involved in initial meetings with Romney rather than an indication of any endorsement strategy based on geography.

Romney visited Capitol Hill in January for meetings with Members, attending separate events set up by Rogers and Rep. Jack Kingston (Ga.).

“Almost half of the Members are not from the South,” McCrery said. “We can say that we have a pretty good representation of all of the regions of the country for Gov. Romney.”

Romney has been most apparent in his efforts to reach out to Capitol Hill, due in part to his need to counter McCain’s natural advantages there and the Arizonan’s status as the frontrunner.

Romney also is working to quell concerns among social conservatives about the evolution of his views on social issues such as abortion and gay marriage.

Romney was well-received at the Republican Study Committee’s retreat Friday in Baltimore, where he addressed House conservatives.

“He has adequately addressed those issues in the private meetings,” McCrery said, adding that the whip team will be spreading that message to their colleagues who have not had personal meetings with Romney.

He said that the endorsements should send the same message to Members’ constituents.

“We’re happy with his explanation of where he is now on those issues,” McCrery said.