Northern Virginia congressional candidate Barbara J. Comstock failed to report that a public-relations company she owns took in a total of $85,000 in 2012 trying to help Mitt Romney become president, an apparent breach of congressional ethics rules.

On Friday, an aide to Comstock, the Republican nominee in the race to replace retiring U.S. Rep. Frank R. Wolf (R-Va.), said that the oversight was unintentional and that the campaign was working to correct the problem after being contacted by The Washington Post.

In January, Comstock, a state delegate representing parts of Fairfax and Loudoun counties, noted her role as owner and partner of the company in a statement of economic interests she is required to file with the Virginia General Assembly. The report said Comstock Strategies took in less than $50,000 the previous year.

In March, Comstock’s congressional campaign filed a federal financial disclosure report noting that the candidate earned $27,000 in income from Comstock Strategies in 2013. The report does not mention her role with the company or how she got the money.

Instructions from the House Committee on Ethics require congressional candidates to declare all reportable assets, including “ownership interests in privately held companies.”

The committee also requires candidates with an ownership interest in companies to report fees earned above $5,000 and a list of clients who paid those amounts.

Comstock’s disclosure report does not mention the $65,000 Comstock Strategies received in 2012 from the Romney campaign or the $20,000 paid by the Republican National Committee, although those groups disclosed the fees in their own Federal Election Commission reports.

Comstock’s disclosure report lists a host of other income sources, including stocks, retirement funds and husband Elwyn “Chip” Comstock’s annual salary as a vice principal at Oakton High School in Fairfax County. (He has since retired from that job.)

On Friday, Comstock’s campaign disclosed the names of other Comstock Strategies clients who paid fees of more than $5,000. They include the Workforce Fairness Institute, a conservative advocacy group, and two public-relations companies.

“Comstock’s ownership of Comstock Strategies is no secret, and we disclosed her salary,” said political consultant Ray Allen, speaking on behalf of the campaign.

“When this was brought to our attention, we immediately contacted the ethics committee,” Allen said. “We are working with them to ensure that all the forms are filled out correctly. We will be filing an amended report.”

A spokesman for John W. Foust, a member of the Fairfax County Board of Supervisors and Comstock’s Democratic opponent in the race, accused Comstock of trying to cover up her past as a Republican political strategist to avoid being seen as too partisan.

“It’s a little hard to believe that someone who made a career out of being an attorney, an investigator and an opposition researcher could have that big of an oversight,” said Shaun Daniels, campaign manager for Foust. “She’s been running away from her record and running away from her past.”

In his disclosure report, Foust — a retired lawyer — listed his $67,450 annual supervisor’s salary, several hundred thousand dollars in retirement funds and wife Marylin Jerome’s annual income of between $100,000 and $250,000 as a partner in an obstetrics clinic in Washington.