A Fairfax Circuit Court judge ordered county police yesterday to provide a list of arrests to individuals willing to pay the cost of compiling the information.

"There is a duty of the police department to furnish what records are available . . . ," Chief Judge Barnard F. Jennings said as he ruled against the county police.

In July the police stopped keeping a log of all people arrested on felony and drunk-driving charges, complaining that the list was used primarily for commercial purposes by lawyers who were soliciting clients from those accused of driving while intoxicated.

Marianna DeDekind, a researcher who sold the names of drunk-driving suspects to lawyers, had asked for the names and addresses of all people arrested in June, saying the Virginia Freedom of Information law required that the names be made public. County police rejected her request, citing the expense of producing the list.

She sued the county and, yesterday, Jennings sided with her. "It is a comparatively simple thing to program your computer" to generate information on arrests when it is requested, he told county attorneys.

The judge also hinted that he would make a similar ruling if other such requests are made to police. "I can't visualize it my ruling being any different," he said.

His order, however, stopped short of compelling the county to reinstate an arrest log or compile a list of drunk-driving arrests as a matter of course. He noted that under the state law individuals requesting information can be charged for the government's costs in compiling the data.

DeDekind's lawyer, Patricia V. Fettmann, argued yesterday that the county police have an "administerial duty" under the Virginia law to provide arrest information to the public.

"The Freedom of Information Act cannot be used at the discretion of public officials as to whether somebody's motives are good enough," Fettmann said. "If that information is being released to the press, then it must be released to everyone. Either the information is confidential or it isn't."

The county police regularly release to the news media the names and addresses of people arrested. Since the log was discontinued two months ago, however, the police have not furnished the information to the general public.

Assistant County Attorney Robert M. Ross argued that the information is available from arrest warrants filed in court.

Ross said the police objected to furnishing the information specifically for what he called "private profit and solicitation."

Col. Alan L. Barbee of the county police said the cost of programming the police computer to generate the information DeDekind wanted would be "fairly substantial."

Fairfax County police arrest about 350 people each month on DWI charges.

Elimination of the log, which was kept at county police headquarters in Fairfax City, had brought criticism from attorneys who made use of it to solicit business from drunk-driving defendants. Other lawyers praised the move, saying that the solicitation of clients from the log was objectionable under the code of ethics that governs Virginia lawyers.