A federal magistrate said yesterday she will order Alexandria officials to turn over information on the alleged use of excessive force by city police since 1976 to a man who claims he was beaten in an incident last March.

In a separate case, a federal jury considering claims growing out of a February 1980 melee at an Annandale convenience store rejected last night allegations of police brutality by five Fairfax County residents. Instead, the jurors awarded a total of $1,400 in damages to a Fairfax police corporal in a counterclaim against three of the plaintiffs.

In Alexandria, U.S. Magistrate Elsie Munsell turned aside vigorous arguments by a lawyer representing the city and its insurance company that the request by Donald R. Neiman, 32, of Harpers Ferry, W.Va., for complaints against city police made over five years amounted to "an incredible fishing expedition."

Attorney David Florin, contending the order would impose undue clerical demands and high costs on the city, first told Munsell there are "a good number" of such complaints. He later said the complaints total "several hundred."

"Alexandria maintains a good-size police department in an urban area," Florin said. "Even if Officer X is rude to a citizen, every one of these complaints is looked into."

Neiman and his lawyer, Frederick Ford of Alexandria, are seeking $510,000 in damages against the city, contending in court documents that Alexandria police have a "de facto policy . . . to summarily punish persons who object to their treatment or question an officer's authority . . . . "

Neiman contends he was beaten with a nightstick and his left arm was broken by police while he was being booked at police headquarters. The alleged incident occurred March 6 after Neiman was arrested and charged with public drunkenness and assault and battery in a fight at Murphy's Pub on King Street in Old Town.

One of the defendants, Officer Stephen J. Thompson, also is the subject of a separate civil suit pending in Alexandria Circuit Court that claims he used excessive force in allegedly firing a shotgun blast through the windshield of a car driven by Ryland Lewis Champlin in an incident on May 18, 1980.

Champlin lost two fingers in the incident, according to court documents.

The six-member jury's decision in the Fairfax case followed 2 1/2 days of conflicting testimony before District Judge Oren R. Lewis in Alexandria.

The claims stemmed from a Feb. 23, 1980, incident in the parking lot of a 7-Eleven store at Rte. 236 and Hummer Road during which two off-duty Fairfax policemen stopped the driver of a van suspected of backing into a parked car and trying to leave the scene.

The driver, Michael Oliver, his wife Linda, and three relatives, Steven and Mark Burney and Mark Burney's wife, Brenda, all of Fairfax, sought a total of $2.75 million in damages, claiming Cpl. Colin W. Morgan used excessive force in an ensuing argument and scuffle in which all six were involved.

The jury sided with Morgan and awarded judgments of $500 against Mark Burney, and $500 against Michael Oliver and $400 against his wife Linda.