Diners in Old Town Alexandria soon may be swizzling spritzers with only the spritz and none of the alcohol if allegations of Virginia liquor law violations are made to stick against six restaurants there.

The establishments face at least temporary loss of their valuable liquor licenses as the result of an undercover investigation that comes only weeks after Alexandria officials complained the state had failed to enforce liquor laws in the city.

Virginia Alcoholic Beverage Commission officials disclosed yesterday that the agency this week accused the restaurants, all but one of which are in the lower King Street area, of violating various state regulations, including rules against allowing workers to drink on duty, serving liquor to drunken customers and permitting patrons to take alcoholic beverages off the premises.

Alexandria officials have said they have been besieged for months by complaints of rowdyism from the Old Town restaruant area and have accused Virginia ABC investigators of refusing to accept complaints from city police or work at night to police the establishments. A legislative committee that heard the complaints last month said the problem was the city's and not the state's.

Virginia State Sen. Wiley F. Mitchell, one of Alexandria's complaining officials, said yesterday he was "delighted" by the investigation. "I'm as confident as I am talking to you that the people who have been most affected by the rowdyism and the problems resulting the concentration of ABC licenses in that area of Old Town will be very pleased that the ABC is exercising its enforcement power," Mitchell said.

"You've got to be pleased that action of this sort will send a message, to those who were charged as well as those who were not, that people in Alexandria won't tolerate it."

The restaurants charged are among the most popular in the Old Town area: 219 Chadwick's, Murphy's Pub, the Corn Exchange, The Lobster Shed and the Fish Market.

All were notified Tuesday of the alleged violations after a three-month ABC probe of between 35 and 40 Alexandria restaurants. All but Murphy's are on lower King Street, the area's busy nightlife thoroughfare.

The investigation was said to be the biggest of its kind in Alexandria in five years. Carl Hayden, who coordinated the ABC effort, said both enforcement and inspection agents began visiting the restaurants in April. Between two and six agents worked undercover each night, he said.

The charges "are not all that serious," said one ABC official, "but they should cause the owners to go back and mend their ways."

"We don't feel we're in any jeopardy," said Don Abram, manager of Chadwick's. Most owners would not comment while their case before the state hearing board was still pending. But one manager did seem resigned to the ABC's findings.

"I do believe it, because I fired a waitress that weekend for that reason," said John Beaudry at Murphy's Pub, which was charged for allowing an employe to drink on duty.

"It's kind of a difficult thing to patrol," said Beaudry. "If a bartender pours himself a shot, it's hard to see, unless it becomes a regular thing. And if it's a busy night, like it was when he [the agent] was here, it's almost impossible.

" guess I'll have to believe it," Beaudry said. "It's their ballpark and you have to play by their rules."