The Justice Department is facing bipartisan criticism for clamping down on government watchdogs' access to documents, in a decision lawmakers say defies Congress and undermines those tasked with rooting out government misconduct. 

The DOJ’s Office of Legal Counsel issued a 68-page memo last week that said the department's inspector general would be required to get permission from the agencies it oversees to obtain wire taps, grand jury testimonies, and credit information. IGs are assigned to audit and conduct internal reviews of federal agencies. 

The decision, first reported in The Washington Post, faced an almost immediate backlash from Capitol Hill and the watchdogs themselves. 

“I strongly disagree with the OLC opinion,” DOJ Inspector General Michael E. Horowitz said in a statement. “Congress meant what it said when it authorized Inspectors General to independently access ‘all’ documents necessary to conduct effective oversight. … Without such access, our office’s ability to conduct its work will be significantly impaired.”

Horowitz is chairman of the Council of Inspectors General on Integrity and Efficiency, the group that oversees IGs across the government. He said that the new rules would lead to waste, fraud and abuse. 

In Congress, Sens. Chuck Grassley, R-Iowa, and Ron Johnson, R-Wis., as well as Reps. Bob Goodlatte, R-Va., and John Conyers, D-Mich., released a statement suggesting the new rules are a clear violation of the Inspector General Act of 1978.

“If the Inspector General deems a document necessary to do his job, then the agency should turn it over immediately,” said Grassley, chairman of the Senate Judiciary Committee. 

Grassley's office said the DOJ already has denied or delayed IG access to records concerning inquiries into Operation Fast and Furious, alleged "sex parties" involving Drug Enforcement Administration agents and other issues. 

He added: “The clear command of that law is being ignored far too often by agencies across the executive branch. By this opinion’s tortured logic, ‘all records’ does not mean all records … The prospect of the Obama administration using this opinion to stonewall oversight, avoid accountability, and undermine the independence of inspectors general is alarming.”

Conyers also said that the IG "should not have to ask permission from the very agency he oversees." He called the opinion a "departure from the plain text of the statute and the intent of Congress." 

All four congressmen are in committees that oversee the DOJ.

DOJ spokeswoman Emily Pierce told the Washington Post that the ruling still allows IG investigators to get sensitive information, and that the department is doing its best to help agents. 

The DOJ has faced criticism in recent years for not turning over information to agents during investigations.

According to both Horowitz and the congressmen, the department has delayed or even blocked many high-profile inquiries. Forty-seven IGs also wrote a letter to Congress last year complaining that the agencies they oversee had refused to release vital information.

Horowitz said he intends to push Congress to pass legislation that would ensure inspectors general independent access to all vital information. 

“We look forward to working with Congress and the Justice Department to promptly remedy this serious situation,” he said. “The agency over which the OIG conducts oversight [should not be] in the position of deciding whether to give the OIG access to the information necessary to conduct the oversight.” 

FoxNews.com's Matt Fossen contributed to this report.