A Fairfax County judge and prosecutor yesterday said there are serious problems in security procedures used by the sheriff's department in moving prisoners in and out of the county courthouse.

Referring to the excape of accused armed robber David Jones last month, Circuit Court Judge William G. Plummer said that only one deputy was guarding the 24-year-old Jones in a courthouse hallway and questioned whether that was sufficient "to minimize the potential of escape."

Jones bolted from the courthouse Nov. 24 after his handcuffs had been removed outside Plummer's courtroom in an incident that Sheriff James D. Swinson said Monday illutrates the ease of escaping there.

Swinson's remarks yesterday drew a rebuke from Commonwealth's Attorney Robert F. Horan Jr.'s top deputy prosecutor, Steven A. Merril, who to escape." The sheriff, who is in charge of courthouse security, had said in an interview that, "If you want to escape from the Fairfax County Courthouse it is an easy thing to do."

Sheriff's officials were warned by Jones' mother two weeks before the escape that her son would attempt to escape, but no extra security precautions were taken. Chief Deputy Sheriff Wayne M. Huggins said yesterday that information about the escape warnings were passed through the department "in a matter of fact nature" and was not deemed significant.

Horan calling courthouse security security "obviously not the best arrangement in the world," described Jones yesterday as "a very logical bet for running." Jones, who faces a variety of armed robbery charges in Fairfax, "has a reputation as the kind of a guy it is hard to keep your hands on," Horan said.

Huggins said yesterday it is standard procedure to transport a prisoner through the courthouse with at least two deputies, but that "practically, if you don't have the bodies you can't do it."

The sheriff department employs 20 deputies to handle 18 courtrooms. Huggins said. On busy days, such as the day Jones escaped, it is impossible to guard each prisoner with two deputies, he said.

In the country courthouse, most of which was built in the early 1950s, prisoners and deputies move through crowded hallways. Because the use of a gun endangers the lives of bystanders. Huggins said the only method deputies can use to stop escapees is "brute force."

The county plans to build a new courthouse with "safe corridors" that will separate prisoners from other courthouse visitors. It is scheduled to be completed in 1981.