Prince George's County officials, concerned that 1,500 county workers will go on strike as early as this week, have threatened union leaders with firings, damage claims and revocation of their contracts if a wildcat walkout occurs.

Reacting to reports that members of five county unions at an impasse in contract negotiations may walk off their jobs, county attorney Robert B. Ostrom dispatched the sharp message to union leaders last Friday warning of the consequences of a strike.

The five locals of the American Federation of State, County and Municipal Employees (AFSCME) represent employes who maintain county roads, operate the landfill and guard the jail. They could legally call a strike only after a complicated arbitration process that has not yet run its course.

Some union leaders last week were considering an immediate strike after an official for a labor panel supervising the negotiations recommended further medication. AFSCME leaders would like the panel to drop out of the negotiations and let a 30- to 60-day countdown toward a legal strike begin.

Ostrom's letter, which was reviewed by County Executive Lawrence J. Hogan, reminded union leaders that "in the event of a strike (that does not follow the ground rules), the county has the right to discipline, by way of discharge, any employe who participates in such a job action."

The letter also warned that a wild-cat strike could lead to revocation of AFSCME contracts and all union privileges.

In the event of any illegal work action, "the letter concluded," the county will hold (AFSCME) and its officers, agents and members fully responsible for any and all damages and losses incurred."

Yesterday, AFSCME leaders said they were unintimidated by the county's warnings and determined to strike.

"I think they were trying to put fear in the hearts of my leadership," said Paul Manner, who is leading negotiations for the AFSCME unions, "but instead the leadership has been infuriated.

"There is no question now that we are going to strike, but we are going to wait the county out and go on legal strike, so all the union members will be protected. And it will not be the county that defines when our strike becomes legal, it will be our union."

Charles Parker, the president of the militant local representing 525 public works employes, said: "We know what we're doing, and we're going to do it, no matter what the consequences."

In addition to dispatching the letter, Hogan and several dozen county officials held a two-hour meeting Friday to plan the county's response to a strike.

The meeting centered on security measures for the county jail and administration building and on possible means of completing work left undone by striking employes, officials said.

County and Union negotiators are scheduled to meet today with members of the mediation panel to review outstanding disputes over work rules and cost-of-living increases.