IRS chief spars with GOP over ObamaCare testimony

“You've been here all of 63 days, she's been here 31 years," Jordan said.

Hall Ingram has become a leading target for congressional Republicans. She formerly led the IRS office that has been accused of improperly scrutinizing conservative groups' applications for tax exemptions and now leads the tax agency's Affordable Care Act office.

Republicans have also sought to leverage the IRS scandal to undermine the healthcare law, which the IRS has a major role in implementing.

“The lady who's at the center of the storm … she's briefing everyone else, but she wont come and brief Congress," Jordan charged, pointing to an internal briefing Hall Ingram gave that included references to the data hub and security concerns.

Oversight and Government Reform Committee Chairman Darrell Issa (R-Calif.) also said he lacked confidence in the hearing because Hall Ingram, "in some inexplicable way," did not testify.

Rep. Jackie Speier (D-Calif.) took issue with Jordan's aggressive questioning.

“If we are going to conduct this hearing as a witch hunt, then I will object," she said.

Werfel defended his appearance before the committee, saying he is the most senior IRS official accountable for the privacy and effectiveness of the federal data hub. The Treasury Department's assistant inspector general for information technology also testified. 

Werfel said he had more relevant technical expertise in the stated subject of the hearing — the security of the federal data hub.