The House approved a major revision of the nation's wiretap laws yesterday to extend the constitutional protection against unreasonable search and seizure to high-technology communications using computers, cellular telephones and satellites.

The legislation, which passed on a voice vote without opposition, had strong bipartisan backing as well as the support of industry and consumer groups, civil libertarians and the Reagan administration.

Known as the Electronic Communications Privacy Act of 1986, the bill is the first major revision of the 1968 Wiretap Act that prohibits eavesdropping on conventional telephone and mail communications without a court order.

The legislation, introduced by Rep. Robert W. Kastenmeier (D-Wis.), chairman of the House Judiciary subcommittee on civil liberties, culminates two years of study. It is designed to fill the void created as technology raced ahead of the 1968 law.

Identical legislation is pending in the Senate.

A report released last October by the congressional Office of Technology Assessment concluded that "the existing statutory framework and judicial interpretations . . . do not adequately cover new and emerging electronic surveillance technologies."

It found that the number of federal court-approved bugs and wiretaps in 1984 was the highest ever and warned that "many innovations in electronic surveillance technology" available to law enforcement agencies "have outstripped constitutional and statutory protections, leaving areas in which there is currently no legal protection against . . . new surveillance devices."

The report included a survey of federal agencies that showed some were already taking advantage of the legal loopholes.

For example, five agencies said they planned to monitor or intercept electronic mail, and another agency said it had already taken such action. Three agencies reported that they were already intercepting cellular phone communications and two others had plans to begin such monitoring. The survey did not include the Central Intelligence Agency, the National Security Agency or the Defense Intelligence Agency.

The communications affected by the legislation range from computer messages and data transmissions to electronic fund transfers and cellular telephone conversations.

Michael Cavanagh, executive director of the Electronic Mail Association, estimated that 5 million Americans use electronic mail, either through commercial networks owned by companies like MCI and GTE Telenet, or through corporate networks linked by computer terminals and telephone lines. Those users transmit some 250 million messages each year, and the number is growing "explosively," Cavanagh said.

The legislation would require a court-approved search warrant for law enforcement officials to obtain a computer message within six months of its generation and a subpoena after that. Most companies eliminate their messages from the system after three months.

Federal agents would be allowed to intercept electronic communications only under a court order from a judge persuaded that the interception may provide evidence of a felony.

Another major focus of the bill is the cellular telephone technology, in which conversations are transmitted by high-frequency radio signals to base stations connected to telephone systems in the cities where the service is available.

The legislation requires law enforcement authorities to meet the strict standards of the federal wiretap statute and obtain a court order to eavesdrop on cellular telephone conversations.

It does not deal with "cordless" telephones, which use a low-frequency radio signal. Since conversations on those phones are often intercepted unintentionally on FM radio receivers, it was decided that users of cordless phones should assume their conversations may be overheard.

The bill picked up major support from the federal law enforcement community with provisions making it easier to obtain court-approved wiretaps. It expands the category of crimes for which a wiretap may be approved, as well as the number of Justice Department officials who can approve a wiretap request to the court.

Earlier this month, the Justice Department notified the House Judiciary Committee of its strong support for the bill.

Jerry Berman of the American Civil Liberties Union also praised the bill, callling it "important privacy legislation."