Conservative Party candidate Doug Hoffman rolled up a series of endorsements Monday in his dark horse bid for former Rep. John M. McHugh ’s upstate New York House seat.

The accompanying financial support increases the likelihood Hoffman’s candidacy will factor heavily in the outcome of the special election, which New York Gov. David A. Paterson is expected to schedule for Nov. 3.

McHugh resigned his post representing the sprawling North Country district after being confirmed as secretary of the Army last week.

Hoffman’s backers include the anti-tax group Club for Growth, which plans to bring its considerable resources to bear on the 23rd District race.

Andrew Roth, vice president of government affairs at Club for Growth, said the group did not have a budget for the contest. That, he said, will be determined by the club’s members and “how interested they are” in supporting Hoffman, an accountant and entrepreneur. However, Roth added, “In this race we think they are going to be wildly interested.”

In its release, the group said Hoffman’s promise not to push for earmarks and to oppose all tax increases created “a clear distinction among the candidates in this three-way contest.”

Hoffman is challenging Republican candidate Dede Scozzafava and Democrat Bill Owens .

In addition to the Club for Growth, the Hoffman campaign also rolled out endorsements on Monday from former Sen. Fred Thompson, R-Tenn.(1994-2003), and the Susan B. Anthony List Candidate Fund, which opposes abortion rights.

Both Thompson and the Susan B. Anthony List encouraged their political action committee supporters to donate to the Hoffman campaign, dubbing him the true conservative in the race.

Scozzafava is considered the favorite, given her higher public profile and political experience — a decade in the state Assembly and five years as mayor of the village of Gouverneur.

She has voted in support of gay marriage and some abortion rights, and that moderate record is expected to help her appeal to the region’s influential independent voting bloc.

Scozzafava has the endorsement of the New York Independence Party and her name will appear on both the Republican and Independence ballot lines.

If Scozzafava loses votes on the right to Hoffman, the beneficiary will be Owens, an attorney and first-time candidate from Plattsburgh, N.Y.