SACRAMENTO — After a state audit found UC administrators hid $175 million from the public while tuition increased, university system President Janet Napolitano apologized Tuesday for the way her office handled the investigation but disputed several audit findings.

Lawmakers at a hearing Tuesday said they are deeply troubled by the state auditor’s finding that the UC president’s office tried to interfere with the audit.

State Auditor Elaine Howle told lawmakers she faced an unprecedented lack of cooperation from the Napolitano’s office while it was under audit. She detailed efforts by the president’s office to edit responses from individual UC campuses to survey questions from auditors.

“We felt that the surveys didn’t reflect an independent voice from those campuses,” Howle said.

Napolitano said the $175 million figure was inaccurate. But she agreed her office should keep clearer budget plans and records, as recommended.

She told lawmakers Tuesday the money in reserves totals $38 million, which she described as a “prudent and reasonable” amount set aside for unexpected expenses. Most of the $175 million Howle identified is already committed to important university programs, Napolitano said.

Napolitano said she coordinated with the individual campuses on their audit responses to ensure they were accurate.

“My team made the decision to work with our campuses to ensure they understood the purpose of the audit and the audit’s scope,” Napolitano told lawmakers. “I am sorry that we did it this way because it has created the wrong impression and detracted from the important fact that we accept the recommendations in the audit report.”

Assemblyman Jose Medina said he found the auditor’s description of interference by the president’s office particularly concerning.

“To interfere in that process, to me, is undefendable,” the Democrat from Riverside said. “I am extremely bothered that there was tampering.”

UC administrators amassed $175 million in undisclosed surplus money over four years even as the university system raised tuition and asked the state for more funding, according to the audit released last week.

“They are not putting California students and families first, particularly with their budget,” said Assemblywoman Catharine Baker, a Republican from Dublin in the East Bay.

In the report, Howle said state lawmakers should increase oversight of Napolitano’s office.