BOSTON, May 29 (Reuters) - A conservative New Hampshire group on Thursday endorsed former state Senator Jim Rubens' run for the U.S. Senate, posing a challenge to fellow Republican Scott Brown, who is also seeking the party's nomination in the September primary.
The Republican Liberty Caucus did not mention Brown, a former U.S. senator for Massachusetts who moved to New Hampshire late last year, in its endorsement but noted that Rubens has lived in the New England state for four decades.
At least four Republicans are vying for the chance to oppose the Democratic incumbent, U.S. Senator Jeanne Shaheen, in November.
The Republican Liberty Caucus is an influential group whose positions jibe with those of Tea Party organizations.
The caucus described Rubens, who has started small businesses that include retail outlets and furniture manufacturing, as a solid challenger to Shaheen.
"Jim's 40-year track record of creating jobs and wealth as an entrepreneur, empowering the citizens of New Hampshire as a legislator, and his ability to solve complex problems while bringing people together is exactly what is needed in this time of great peril," said Aaron Day, chairman of the Republican Liberty Caucus.
Brown, a native of New Hampshire, represented neighboring Massachusetts in the Senate from 2010 through 2012 after winning a surprise victory in a special election following the death of Democratic Senator Edward Kennedy. But Brown was defeated in his first re-election bid by Democrat Elizabeth Warren.
A Dartmouth College poll of 400 registered voter released last month showed Shaheen with a narrow 39.2 percent-to-35.6 percent lead over Brown in a theoretical general election matchup.
Her lead was modestly wider over another potential Republican challenger, Bob Smith, who held the seat from 1990 till 2003 but was more substantial over Rubens or another Republican contender, Karen Testerman. (Reporting by Scott Malone; Editing by Jonathan Oatis)