TRENTON, N.J. (AP) _ Conversations tape-recorded last year among three political associates over a cordless telephone have forced New Jersey law enforcement officials to try to decide where modern technology fits into state and federal wiretap laws.

Because cordless telephones are so new to the market, no court rulings on any cases involving the devices have been issued, and the lack of precedence has members of the Division of Criminal Justice of the attorney general's office disagreeing over what laws should apply.

But George Spanos, who had cordless telephone conversations taped last December, said he has no doubt such recordings violate the law.

''I look at it as a total invasion of privacy. This is a small town and there was a lot of talk about this. There was speculation that I had done something wrong or said something illegal. It hurt me and my family,'' said Spanos, a member of the Plainsboro Township Committee.

According to Spanos and the Division of Criminal Justice, someone recorded hours of conversations that Spanos had over his cordless telephone with two political associates, whose identities have not been made public. Spanos was a newly elected town committee member, a non-salaried part-time position.

The conversations' centered on a proposal the Republican Party had backed to establish controls for housing developments on farm land.

But Spanos, an employee of the New Jersey Office of Telecommunications and Information Systems at state police headquarters in Ewing Township, said he also had discussed family and personal matters.

''Why anyone would want to tape me I have never figured out,'' he said. ''The development issue was something that had already been discussed at length in public, there was no secret.''

Donald R. Belsole, the director of the Division of Criminal Justice, said the tapes of Spanos' conversations could form the basis for criminal charges, but that he and his staff could not agree whether wiretap laws apply to the case.

Federal law says that people convicted of intercepting the conversations of others without authorization can be fined $10,000 and sentenced to five years in prison.

Belsole said he believes that New Jersey's statute, which calls for the same penalties as the federal law, applies to the Plainsboro case. But because other attorneys in his office disagree, he has ordered his staff to prepare a report on the issue.

Cordless telephones operate as radios between the handset and a base in the user's house, where conversations go into the regular telephone system and over the wires.

Conversations over the devices frequently can be heard by neighbors over their own telephones or on AM and FM radios. Accidental interceptions are not illegal, Belsole said.

If people record the conversations and try to use them, however, they may be breaking the law.

Ennis Coleman, an engineer in the Philadelphia office of the Federal Communications Commission, said the agency updated its 1935 regulations last year to ban the unauthorized use of such transmissions.

No court decisions have been issued on the subject, Coleman said. He blamed the phones' popularity and the narrow range of frequencies assigned to them for the interference problems.

If consumers buy the phones at about the same time from the same store, their phones could be on the same frequency, he said.

Lawrence West, an assistant Middlesex County prosecutor, said he knew who recorded Spanos' conversations but, as did other officials, declined to identify the person because of the state's investigation.

The only comment West would make about how the state acquired the tapes was that Peter Cantu, a Democrat on the township panel, obtained a copy of them and that they eventually were turned over to the criminal justice office.

Cantu's attorney, Steven Richman, said he had found only two state court cases involving cordless phones: in Kansas and Rhode Island. In both cases, he said, the courts had admitted evidence obtained through the recording of conversations over the instruments.