Republican gubernatorial candidate Knute Buehler called on Gov. Kate Brown Monday to appoint an independent lawyer to investigate why Oregon overpaid more than $74 million in Medicaid money to health care organizations.

Buehler, who is an orthopedic surgeon and lawmaker from Bend, also called for Brown to recoup the money and publicly release all records of her administration's communications about the overpayments.

"The effective delivery and transparent administration of providing health care to Oregonians should not be a source of partisan division," Buehler wrote in a letter to Brown.

Buehler said he supports Medicaid and the expansion of the health insurance program for the poor under the Affordable Care Act. But Oregon's problems administering the program have chipped away at the state's reputation for health care innovation and undermined public trust in state government, Buehler said.

Oregon overpays more than $74 million for Medicaid, governor kept in the dark

At an event Monday in Portland, Brown did not directly answer questions from reporters about whether she would appoint a lawyer to investigate the overpayments and release communications records as called for by Buehler.

"My goal is to make sure that Oregonians have access to health care," Brown said, adding that she is also committed to "ensuring that taxpayer dollars are spent efficiently and effectively."

Brown said her administration works hard to fulfill public records requests, and "all of our public records are available for release."

Brown recently brought in new administrators to lead the Oregon Health Authority, and those employees are still working to determine the full extent of overpayments. The most well-understood problem involved Oregonians who were old enough to qualify for Medicare and poor enough to qualify for Medicaid. Medicare pays first and should have covered most of those patients' costs, but instead the state signed them up for the most expensive type of Medicaid.

Oregon retrieved $10 million of those overpayments in 2016 and returned it to the federal government, and the state could be forced to return the remaining $64 million.

State officials acknowledged the problem last week when they released public records about the overpayments in response to a request from The Oregonian/OregonLive. A couple hours after the records release, Brown sent out a press release in which the governor said she only recently learned of the overpayments. A spokesman for the governor said Oregon Health Authority officials withheld the information from Brown.

-- Hillary Borrud; 503-294-4034; hborrud@oregonian.com; @hborrud