The threat of a primary challenge from the right has made Republicans skittish about compromising with Democrats on taxes, according to Rep. Barney Frank (D-Mass.).

Asked whether Republicans and Democrats could settle on a tax reform compromise, Frank, the ranking Democrat on the House Financial Services Committee, said he worried that Republicans feel too much pressure from the right to strike a deal.

"I do question whether or not the influence of the Tea Party types is too strong for that to happen. Because I will tell you, I know, look, you have a lot of former colleagues, you talk to them," Frank said Tuesday to MSNBC's Joe Scarborough, who served in the House as a Republican from Florida.

"The fear of losing to a [Rep.] Michele Bachmann [R-Minn.] follower in a primary has unfortunately become a major determinant of congressional action. We have Republicans who I've talked to who say, 'Yes, but I'm worried about my primary,' " Frank said.

Frank's comments come as a bipartisan group of senators — the so-called Gang of Six — negotiate a deficit-reduction plan that is likely to include a tax-reform component. Sen. Tom Coburn (R-Okla.), one of the most prominent fiscal hawks in the Senate and a member of the group, recently voiced his opposition to any "significant" tax hikes from the Gang's proposal.

Coburn's statement suggests that some of the members of the group are opposed to allowing the Bush tax cuts for some of the wealthiest Americans to expire.

President Obama has called for a long-term deficit-reduction deal that rolls back the tax reductions for the wealthy that were passed when President George W. Bush was in office.