The president of the Prince George's County police union said yesterday that if other county public employes strike next week his union intends to support them, possibly by refusing to cross picket lines or by a work-to-the-rule job action.

Laney Hester, president of the Fraternal Order of Police, said his union bases its support on the belief that County Executive Lawrence J. Hogan has failed to bargain in good faith with the American Federation of State, County and Municipal Employees, which represents 1,500 public employes in the county.

"We are very sympathetic . . . and we will not be used as scabs or strike-breakers if it comes to a strike,"Hester said. The public employes' union has set a Tuesday strike deadline in its longstanding contract dispute with the county.

Hogan was unavailable for comment yesterday. Kenneth Duncan, county administrative officer, said, "I don't know that this is Hester's affair. No one is planning to use the police as strike breakers. We have a duty to ensure the safety of citizens and employes who wish to enter the county facilities."

Lawrence Hogan Jr., the county executive's son and one of his top aides, said that if police participate in a strike, "I guess we'll have to fire them." He said jail guards, who were enjoined by a judge this week from participating in a strike, would be fired if they walked off their jobs.

Since July, the employes, including those guarding the county jail, operating the landfill and inspecting new homes, have been without the cost-of-living increases granted other county employes.

Three weeks ago, the contract dispute seemed to be resolved when Hogan's negotiators and the union signed a tentative agreement that granted the public employes a 4.7 percent wage increase.

That agreement was ratified by the union membership but was vetoed by Hogan who cited a number of objections and apparently believed that if he signed, it would look as though he had been forced into accepting a settlement because of pressure from his political rivals on the County Council and the union.

The union filed an unfair labor practice charge as a result of Hogan's veto, accusing him of failing to bargain in good faith. A decision on that charge is expected this week.

Last Friday, the union informed the county that its members will walk off the job March 18 unless an agreement with the county is reached.

With the strike deadline approaching, Hogan has initiated a series of legal moves to stave off or delay a walkout and his department heads are prekparing strike contingency plans to allow the county government to continue operating in the event of a strike.

In each department, supervisors have been determining which employes are union members and how to pick up their work loads if they walk off the job. a

The personnel department has been compiling lists of qualified persons who have previously applied for county jobs. Those applicants would be hired on temporary basis, county officials said.

In the Public Works Department which would be the one hardest hit by a strike, the department head and his supervisory staff have been learning to drive bulldozers and other heavy equipment in order to keep the county landfill operating.

The Sheriff's Department has set up a special "strike force" of deputies who previously worked in the county jail, where 110 employes are union members. Officials said the deputies could operate the jail in the event of a strike.

The public employes union is contesting the court injunction that bars the guards from striking.