The Supreme Court of the Philippines today ruled that the testimony given by armed forces chief of staff Gen. Fabian Ver and seven others before an official board of inquiry cannot be used against them in their trial in connection with the murder of opposition leader Benigno Aquino Jr.

The high court's ruling clears the way for Ver's acquittal because most of the evidence used against him comes from his testimony before the fact-finding board, several lawyers said.

The ruling will not necessarily have the same effect on the other defendants and still leaves open the possibility of a finding that Aquino's death was a result of a military conspiracy, according to Andres Narvasa, general counsel to the fact-finding board.

Ver's lawyer has said he would seek dismissal of charges against his client if the high court upheld an earlier ruling of the trial court, as it did today. Ver, the closest military adviser to President Ferdinand Marcos, has been on leave since October, when the fact-finding board concluded that Aquino was killed as a result of a military conspiracy and not by a lone Communist gunman, as claimed by the government.

Marcos has pledged to reinstate Ver as chief as staff if he is acquitted. The United States, however, has made clear to its ally in the Pacific that it considers Ver an obstacle to implementing the serious military reforms necessary to combat the country's growing Communist insurgency.

In Washington, there was no immediate comment from the State Department. But congressional sources who have been following the case said Ver's reinstatement could affect the amount of U.S. military aid in the next fiscal year.

Today's ruling upholds the trial court's decision to throw out the main body of evidence against Ver, Manila police chief Maj. Gen. Prospero Olivas, and six others charged as accessories in the killings of Aquino and Rolando Galman, the alleged hired gunman who was killed immediately after Aquino was shot. Seventeen other defendants are charged as principals and one civilian is charged as an accomplice in connection with the Aug. 21, 1983, airport assassination of Aquino, Marcos' political archrival who was returning to the Philippines after three years of self-imposed exile in the United States. The trial had been suspended to await the Supreme Court ruling and is expected to resume next week.

The Supreme Court decision centered on whether the witnesses had incriminated themselves before the fact-finding board as suspects since they were not told of their right to remain silent.

Chief Justice Felix Makasiar told reporters the vote was 10 to 3 with Justices Claudio Teehankee, Lorenzo Relova and Amuerfina Herrera dissenting.

The Philippines Supreme Court has had a reputation in the past of siding with Marcos, but in the last year it has shown more independence in its decisions.

Board lawyer Narvasa, who is in New York, said in a telephone interview that the prosecution can move for a reconsideration within 15 days. If the court sustains the ruling, he said, the prosecution can still pursue perjury charges against Ver stemming from his testimony before the fact-finding board.

Bienvenido Tan, another lawyer of the fact-finding board that investigated the assassination for nearly a year, said the prosecution's case "has been weakened very badly." There may be other evidence such as the photo chronology of the assassination and the testimony of Rebecca Quijano, who said she saw a soldier kill Aquino, he said, "but the testimonies of the others were important to prove there was a conspiracy and that the soldiers were lying."

As part of the military conspiracy, the fact-finding board concluded that a soldier killed Aquino and that Galman had been set up to take the blame. A majority report from the board included charges that Ver lied about military monitoring of Aquino's movements before his return to Manila.

In its ruling, the court said: "It is not far-fetched to conclude that they were called to the stand to determine probable involvement. Yet they have not been informed or . . . even warned while testifying, of their right to remain silent and that any statement given by them may be used against them."

In his dissenting opinion, Justice Teehankee said that a warning to the witnesses "would be an exercise in absurdity and futility" because they were eager to testify to support the government version that Aquino was killed by hired assassin Rolando Galman.

Teehankee said the "unprecedented grant of immunity" may also affect the 18 others on trial and leave the "people holding an empty bag of excluded testimonies and evidence. The unjustified exclusion of evidence of the prosecution may lead to the erroneous acquittal of the accused or dismissal of the charges . . . "

Lupino Lazaro, the lawyer for the family of Aquino's alleged killer, Galman, said the decision "is conclusive proof of the temerity of President Marcos to use the vast resources, powers and influence of his office in order to ensure the acquittal of the infamous Marcos loyalists."

"I grieve in awesome bewilderment," Lazaro said, "at the nerve of some of our justices and judges today who can still afford to throw their unqualified support for a leadership that steals the people's money, kills its political rivals, kills newsmen, students, laborers, lawyers and other freedom fighters, violates human rights and cheats in every known election, referenda or plebiscite."