The District’s ethics board said Thursday that the city government’s internal watchdog agency has refused to share investigative reports and other records, thus imperiling its role in holding wrongdoers accountable.

The Board of Ethics and Government Accountability voted to authorize the issuance of subpoenas to the Office of the Inspector General, an extraordinary breakdown of relations between two government bodies charged with preserving the public trust.

“We have cases that are hanging in the balance,” said Robert J. Spagnoletti, the board’s chairman, during a public meeting Thursday. Without access to the records, he said, the board would be unable to take action in numerous cases involving government wrongdoing.

Inspector General Charles J. Willoughby said in a rare interview Thursday that he was willing to share some information with the board but the demands for unfettered access to his investigative files threatened his office’s independence.

“We can’t just let someone look at our entire files,” he said. “We have to determine what is relevant and appropriate.”

The dispute was brought to a head by the case of a city employee who, Willoughby’s inspectors found, had improperly used a disabled-parking placard to park near his office at the Department of Consumer and Regulatory Affairs.

A hearing on the sanctions has been scheduled for later this month, but Director of Government Ethics Darrin P. Sobin told Spagnoletti and board member Laura M. Richards at Thursday’s meeting it could not go forward because Willoughby has refused to share key documents related to the case. Under the board’s rules, the subject of a disciplinary hearing is entitled to review a wide range of material related to his or her case.

Willoughby said he has made some materials available to the board and added that his office is treating the ethics board the same way it treats other entities it works with, including the U.S. attorney’s office and the District’s attorney general. “We’ve never encountered this sort of reaction from other agencies,” he said.

The Office of the Inspector General this year carries a $15.7 million budget and employs dozens of investigators among its 112 employees to carry out its mission to “promote economy, efficiency, and effectiveness, and to detect and deter fraud, waste and mismanagement throughout the government.” It has no power to levy sanctions.

The ethics board can take a variety of actions for violations of the code of employee conduct and other misdeeds. But it has a budget just over $1 million and employs nine people, only two of whom are investigators.

The ethics board, created by the D.C. Council in 2011 as part of a wide-ranging ethics overhaul, began operations in October and has already levied high-profile sanctions against three D.C. Council members. Sobin said Thursday that the inspector general’s office had not referred any cases to the board for adjudication until last week, when two cases were referred for sanctions.

Sobin said Thursday that the dispute has entered a “critical stage” and must be resolved if the board is going to hold city employees accountable. “We are aware of items we absolutely need that are in the file,” he said of the parking-placard case. “Failure to [obtain them] will stop the enforcement proceeding dead in its tracks.”

Spagnoletti described an extended series of acrimonious conversations and exchanges of correspondence with Willoughby that resulted in what he termed a “logjam.”

He and Richards voted Thursday to authorize the subpoena in the absence of a more amicable resolution. A third member of the board, Deborah Lathen, was not present Thursday.

Sobin said he was “loath to subpoena a sister entity who’s supposed to be working cooperatively with us” but added that “our survival depends on” being able to have access to investigative records.

Willoughby called the dispute “extremely unfortunate” but showed no sign of backing off. “I’m entrusted with maintaining the independence and integrity of this organization,” he said. “For me to do otherwise, I’ll say this, would be a dereliction of my duty as inspector general, and I’m not doing it.”

Both Spagnoletti and Sobin raised the possibility of a legislative fix, and it appears that one might be in the offing.

D.C. Council member Kenyan R. McDuffie (D-Ward 5), who chairs the council panel overseeing both agencies and who has recently questioned Willoughby’s effectiveness, said Thursday that legislation he recently introduced would give the board expanded rights to review records from city agencies, including the inspector general’s office.

“They should have access to the documents they need to conduct their mission,” he said. “Just like I think that the IG should have the authority to investigate what it needs to ferret out waste, fraud and abuse.”

McDuffie said he disagreed with Willoughby’s interpretation of his office’s independence. But he suggested it would be unwise for the ethics board to subpoena the office, leading to a potentially extended legal battle.

“It’s not going to be the most useful and efficient use of government resources if they have to fight it out in court,” he said.