The Justice Department's inspector general said Tuesday that his staff is routinely blocked from getting access to documents it needs for audits and reviews of the department and its law enforcement agencies.

The interference causes delays in investigations and has several times required the intervention of Attorney General Eric Holder to ensure that the records are ultimately turned over, Michael Horowitz, the inspector general, told members of Congress.

Horowitz's appearance before the House Judiciary Committee came one month after nearly 50 inspectors general from a broad spectrum of federal agencies complained in a letter to Congress about similar obstruction from the departments they monitor.

In the last few years, the FBI has denied access to records that should be provided under federal law, including grand jury materials, an organizational chart and electronic surveillance information, Horowitz testified.

He said the refusal to grant routine requests stalls investigations, including a recent one on FBI material witnesses, such that officials who are under review have sometimes retired or left the agencies before the report is complete.

The inspector general's office has in several instances received the requested information only after Holder, or Deputy Attorney General Jim Cole, have granted permission.

"We should be able to get direct access to information," Horowitz said.

If a witness wants to directly approach the inspector general's office with information, they should be able to do so, he said.

"We shouldn't have to go make a request to the legal counsel, have them go look through the documents and get them eventually -- hopefully," he added.

The Justice Department in May asked its Office of Legal Counsel to issue a legal opinion addressing the objections raised by the FBI.

The FBI did not immediately respond to a request seeking comment.

"This is so outrageous," said Rep. Jason Chaffetz, R-Utah. "The inspector general should have unfettered access to all the information they want. And when it's gotten to the point when they can't even see an organizational chart, it's reached the level of absurdity that must be addressed immediately."