Prince George's County Sheriff James Aluisi announced yesterday that he has decided to disband a force of more than 100 volunteer deputy sheriffs because it would be "in the best interests of the department."

The 118 volunteer deputies, who have full arrest powers and carry sheriff's deputy badges, were authorized until recently to carry handguns, even though some of them never completed a state-mandated gun training program.

In a prepared statement, Aluisi said he reached the decision in light of a recent state attorney general's office recommendation that he terminate the eight-year-old volunteer force, which includes some of his political supporters, friends and relatives.

Assistant Attorney General Emory A. Plitt Jr. said his office had given Aluisi copies of two earlier rulings by the state attorney general's office that the Prince George's volunteer deputy force was not permitted under state law.

The first, in 1978, said Aluisi's predecessor, Don Ansell, did not have the authority to empower volunteer deputies. The second, in 1979 in response to a request from Aluisi to clarify the earlier opinion, declared that as far as state officers were concerned the volunteer force was legally "null and void."

Aluisi said earlier this year that he had not disbanded the group then because he had been told he could not maintain a "standing" force; this group was a "pool" of people he could use if they were needed, he said.

"There's no change in our office's interpretation of what the law says," Plitt said. "We told [Aluisi] what his options were and what he had to do to make the deputies legal. He has to go to the state legislature to get the law changed to allow him to do it."

Aluisi could not be reached for comment. A spokesman, Arthur DiGennaro, said the sheriff is sending letters to the 118 volunteers asking them to return any equipment issued from the department. DiGennaro said he did not know whether Aluisi would ask the legislature to change the law.

The two-term sheriff came under fire recently for using the volunteer deputies during roundups of parents who are behind in child-support payments. Aluisi has said that using the volunteers, who receive no pay, saved the county about $10,000 that otherwise would have been paid as salary in the last roundup.

Prince George's County Council member Anthony Cicoria, who had called for an investigation of the volunteer force after media reports about its operations, said yesterday he was "very pleased" that Aluisi is disbanding the force. "It should have been done a long time ago," Cicoria said. "We should never have had this in the sheriff's deparment."

Some of the volunteers are former law enforcement officers. But among the others were doctors, business owners, a real estate developer, a minister and Aluisi's father, cousin and uncle.