Arlington police seized 10 cassette tapes, a telephone amplifier and speaker, a Sony recording system and some electronic listening devices from an automobile dealership after informants told them that the telephone conversations of employes may have been taped illegally for more than a year.

Neither police nor officials of the company, Brown Arlington Honda, would elaborate on the seizure, which was disclosed in papers filed yesterday in Arlington Circuit Court.

Assistant Commonwealth's Attorney Kenneth E. Melson said recordings, believed to have been "illegally intercepted," were among the items found during a Dec. 15 search of the dealership, located in the 3900 block of Lee Highway. No charges have been filed but Melson said results of the investigation will be presented to a grand jury Jan. 17.

Violation of Virginia laws regarding the unlawful interception of conversations by telephone and the possession of certain electronic devices used in wiretapping carries penalties of up to five years in prison and a $1,000 fine.

According to an affidavit filed in the court, Arlington police requested a warrant to search the dealership after an FBI agent told them of two employes who said they had listened to recordings and tapes on which they were surprised to hear their own voices or the voices of other employes. The informants said the recordings involved private conversations or those between salespersons and prospective customers, according to the statement by Detective Steve Kincheloe. One employe reported seeing at least 50 cassette tapes and other recording equipment, he said.

Howell declined to comment yesterday. Edmund McLean, attorney for the company, said he knew of no illegal use of the seized equipment.