Bowing to pressure from the state legislature, Maryland's chief public defender issued a letter this week telling the lawyers employed by the state to defend poor persons that they must sharply curtail any private practice they maintain.

The new orders have angered a number of those lawyers who say that they need the civil work to compensate for their low state salaries. Officials in Montgomery and Prince George's counties, who said public defenders commonly maintain private practices, said they fear the letter will cause several public defenders to quit.

More than 160 public defenders around the state recently received a memorandum from their chief, Alan H. Murrell, saying that "the private practice of law . . . is hereby prohibited between the hours of 8:30 a.m. and 4:30 p.m. during the five-day workweek . . . "

Murrell said that memo is merely a reiteration of existing policies, but James Kenkel, chief of the Prince George's public defender office, said Murrell is "changing the rules under which we were hired."

Public defenders, who are paid by the state to represent indigent persons charged with crimes, have never been allowed to practice criminal law privately. They may practice only civil law, which includes cases such as divorces, contracts and wills.

The memo was accompanied by a letter personally addressed to each public defender asking that he or she decide by July 2 to resign, agree not to engage in private practice during the workweek, or take a cut in salary to compensate for the part-time work being done in private practice.

Murrell said the letter was sent out because a legislative appropriations committee asked him to curtail the public defenders' outside legal activities.

"I haven't prohibited the private practice of law entirely . . . I wouldn't be able to attract anyone . . . . This is as far as I'm willing to go," Murrell said. "If they want to practice at night, more power to them."

The issue is expected to be discussed today when the deputy public defenders from each county meet with Murrell in Frederick.

Kenkel, whose office employs 15 staff lawyers, said yesterday that the memo is "a real slap in the face." Kenkel said public defenders in his office carry the largest case load in the state, and they have always fit civil work around their criminal cases. They do not get paid overtime and most do their private work in offices and rarely need to appear in court.

"We have a staff that's very upset," Kenkel said after a staff meeting yesterday. "If it's not rescinded, I think this could have a disastrous affect on this office." He said several of the more seasoned lawyers may quit.

The problem, Kenkel said, is money. Public defenders are paid at least one grade lower than other state lawyers such as prosecutors and county attorneys. Most prosecutors in the state are not allowed to have a private practice.

Kenkel said the average lawyer in his office is 35 years old and makes about $30,000 a year.

Murrell agreed that the state ought to pay public defenders more, but said that the restrictions on private practice are to "protect the professionalism of the agency."

J. Theodore Wieseman, public defender chief in Montgomery County, believes the new policy will cause only two of his 14 full-time lawyers to quit, but he said the problem is much more severe in other counties. "We have advocated that if we can only get decent salaries, everyone would give up private practice," he said.