President Barack Obama’s choice to head the Internal Revenue Service told senators Tuesday he will work to restore public trust in the wake of the tea party scandal, even as the IRS takes on new responsibilities administering the president’s health care law.

At the same time, John Koskinen warned that budget cuts are threatening the agency’s ability to collect revenue effectively and enforce the nation’s tax laws.

“In every area of the IRS, taxpayers need to be confident that they will be treated fairly, no matter what their background or their affiliations,” Koskinen told the Senate Finance Committee. “Public trust is the IRS’ most important and valuable asset.”

Obama nominated Koskinen, a retired corporate and government official with experience managing numerous organizations in crisis, to take over the IRS in August.

It appears likely the Senate will confirm the 74-year-old turnaround specialist to a five-year term, which would last beyond Obama’s stay in office. Both Sen. Max Baucus, chairman of the Finance Committee, and Sen. Orrin Hatch, the committee’s top Republican, said they support Koskinen.

Regardless, Koskinen’s confirmation hearing was cut short Tuesday after Senate Republicans invoked a little-used rule that prohibits Senate committees from meeting later than two hours after the Senate starts its daily session. The Senate opened at 10 a.m., so the Finance Committee’s hearing, which was interrupted by several votes in the Senate floor, was abruptly stopped at noon.

The rule is routinely waived, but Senate Republicans are upset that Democrats recently changed Senate rules to make it easier for them to confirm many of the president’s nominees without Republican support.

Baucus, a Montana Democrat, said the hearing will resume this morning. Baucus said he hopes the committee will approve Koskinen’s nomination quickly, sending it to the full Senate. The IRS has been without a confirmed commissioner for more than a year.

“As far as I’m concerned, the top priority for the next IRS commissioner should be to restore the agency’s damaged credibility with the American people and their trust that the actions taken by the IRS are fair and impartial,” said Hatch, of Utah.

The IRS came under fire in May when agency officials acknowledged that agents had improperly targeted tea party and other conservative groups for additional scrutiny when they applied for tax-exempt status. The Justice Department and three congressional committees, including the Finance Committee, launched investigations.

The investigations, which are ongoing, have shown that IRS workers in a Cincinnati office started singling out conservative political groups in the spring of 2010, and continued to do so until 2012. IRS supervisors in Washington oversaw the targeting, but there has been no evidence released so far that anyone outside the IRS knew about the targeting or directed it.

The IRS, which is part of the Treasury Department, will be in charge of enforcing the mandate that most individuals have health insurance, and collecting fines from people who don’t.

Koskinen said the IRS has done its part to effectively prepare for the health law. But, he warned, budget cuts are undermining the agency.