The D.C. Office of Campaign Finance is accusing Mayor Anthony A. Williams of violating city law by not disclosing two consulting arrangements with city contractors that paid him $40,000 last year and has ordered the mayor to bring his personal financial records to a hearing next week.

In a notice sent to Williams on Friday, campaign finance director Cecily E. Collier-Montgomery charged Williams (D) with violating a clause in the D.C. Code that requires candidates for public office to report any changes in their income within 30 days. Under D.C. law, Collier-Montgomery and Kathy Williams, the campaign finance office's general counsel, could fine the mayor up to $1,000.

The statement in question was filed by Williams on July 17, 1998, a month after he resigned his $118,000-a-year job as the District's chief financial officer and announced his candidacy for mayor. The statement indicated that Williams did not have any outside income.

Two weeks later, on July 31, Williams signed a $30,000 consulting contract with the Arthur Andersen & Co. accounting firm. On Aug. 6, Williams signed another consulting contract, with NationsBank, for $10,000. The mayor has said that he took on the work to provide his family with an income while he ran for office, and that he was not involved in any work involving D.C. government.

Under D.C. law, both arrangements should have been reported by Williams within 30 days. However, he did not report the income until last month, in financial statements that all D.C. officials are required to file annually.

The letter from Collier-Montgomery states that Williams "failed to modify his financial disclosure statement, dated July 17, 1998, for calendar year 1998."

The mayor has acknowledged as much and 10 days ago apologized for not reporting the consulting income sooner.

"I should have disclosed the fact of my outside employment earlier and inadvertently failed to do so," Williams said then. "For this oversight, I am sorry."

Peggy Armstrong, the mayor's spokeswoman, said yesterday that "the mayor received the letter [from Collier-Montgomery], and he plans to cooperate fully."

Collier-Montgomery said that Williams's report of the work he did while outside D.C. government -- which included a nearly two-month period when he was the mayor-elect -- is still under review by her office, and that having him appear at a private hearing June 16 would be part of that process.

"We determined we would schedule it for an informal hearing because there are apparent violations" of the D.C. Code, she said. "It's our normal process."

Reports in The Washington Post of Williams's consulting arrangements -- and of his initial reluctance to provide details about his work for Arthur Andersen and NationsBank -- led some council members to question whether the mayor had violated conflict-of-interest and campaign ethics laws.

Council member Kathy Patterson (D-Ward 3), chairman of the council committee that monitors campaign finance matters, recently asked Collier-Montgomery to examine whether Williams had violated D.C. law by not reporting his outside income soon enough.

Patterson noted that according to Williams's contract with Arthur Andersen, he had met with officials of the company on July 1, 1998 -- more than two weeks before he filed last year's financial disclosure statement -- to discuss municipal issues.

Patterson told the campaign finance office that documents show that Williams was compensated for that meeting, and she asked whether he should have reported the Arthur Andersen arrangement on his July 1998 disclosure form.

"In view of the Office of Campaign Finance, does this . . . constitute a false, misleading or incomplete statement?" Patterson asked Collier-Montgomery. "If so, do you consider this to be grounds for civil and criminal prosecution?" Patterson was in meetings and unavailable to comment late yesterday.

When first questioned about the consulting, Williams said he was under no legal obligations to provide details on what he did for Arthur Andersen and NationsBank.

He later agreed to provide specifics about his work, indicating that he participated in 10 meetings with Arthur Andersen officials to discuss government issues, gave a speech at the company's annual gathering last year and critiqued a report. For NationsBank, Williams attended one luncheon meeting.