Arlington County government and business leaders took the offensive yesterday in an effort to kill a long-discussed plan to move 18,000 Navy employes from Crystal City to the Washington Navy Yard, a relocation the Northern Virginians said would be devastating to the county's economy.

A report, released yesterday and paid for by the Arlington Chamber of Commerce and the county, presents a plethora of statistics to attack a General Accounting Office report supporting the move.

The GAO report says the Navy could save $263 million over the next 30 years by moving out of leased space in Arlington, but the chamber report presents a different picture.

It says the move would cost the Navy, in terms of today's dollars, at least $5.2 million over the 30 years and potentially as much as $74 million.

Spokesmen for the Navy and the GAO said yesterday they would not comment until they analyze the report.

"I can't find anybody affected that this move makes any sense for," County Board Chairman John G. Milliken said at a press conference. "It makes no sense for the Navy, the federal government or Arlington."

"The Navy and the businesses associated with the Navy are our business base," he said. "It makes no sense to lose all or part of that base." The report said that in addition to the Navy personnel, another 12,000 jobs in the county are dependent upon the Navy's presence.

If the Navy employes move, Arlington could lose $71.2 million in tax revenues and 37,600 jobs in the next 15 years, said David Guernsey, the chamber's president, referring to the report.

The highrise offices and hotels of Crystal City, where 92 percent of the Navy's 18,635 Northern Virginia employes are located, would be especially hurt, Guernsey said. Office vacancy rates there could reach 19 percent and some hotels could go out of business, he said.

Both Milliken and Guernsey also discussed other implications of a move: the increase in traffic into the District, the lack of restaurants and other stores at the yard, and future recruiting problems.

Guernsey added that businesses in both Crystal City and nearby Pentagon City have been hurt by the "uncertain climate" surrounding a possible move.

Since 1981, when the move was first proposed, Arlington officials and members of the Virginia congressional delegation have engaged in battles almost every year to block the government from moving the Navy employes. They are directly or indirectly responsible for 19 percent of the county's work force and 26 percent of its office space.

"The study will help us kill it up here in Congress," said Rep. Frank R. Wolf (R-Va.), whose district includes Arlington. "We'll go to the Defense Department to share it with them, and see if we can keep it from getting proposed every year." Although there is no current proposal before Congress to move the offices, Wolf said: "We have to keep driving a stake in this every year . . . . Clearly there are people in the Navy who still want it."

"Each year, we've been charging up San Juan Hill with the troops to say to those in charge . . . that it makes no sense; and each year they've agreed," Milliken said. "We come back down, and each year we have to go back up."

The report may help sway those on Capitol Hill who advocate a move, said Leonard Bogorad, vice president of the Real Estate Research Corp., the consulting firm that conducted the $84,000 study on the potential impact of a Navy move.

Bogorad said he had more recent data than that used in the GAO report. The chamber report, he said, uses a complicated formula to project future costs, and relies on different estimates of rents and costs from those used by the GAO. NAVY'S IMPACT ON ARLINGTON COUNTY Current impact:

*19% of Arlington jobs are due to the Navy, including 17,422 Navy employes and another 11,825 contractor, hotel, retail and service jobs.

*49% of the gross receipts of firms in Crystal City are directly or indirectly due to the Navy.

*Navy and contractors occupy 26% of Arlington's office space.

*9.3%, or $13.8 million, of Arlington's tax revenues are an indirect result of the Navy.

*Virginia receives $34.8 million annually as an indirect result of the Navy's presence in Arlington. Impact of a move to the Navy Yard:

* Office and hotel vacancy rates would skyrocket, particularly in Crystal City. Arlington County would have 37,600 fewer jobs by 1995.

*Crystal City retail and hotel revenues would drop by one-fourth between 1992 and 1995 (in constant dollars).

*1995 Arlington tax revenues would be $25.4 million lower, requring a 12% tax increase.

*Annual Virginia revenues from Arlington would be $25.7 million lower by 1995.