In a ruling harshly critical of the U.S. Customs Service, a federal judge yesterday ordered the return of more than $7.6 million in jewelry, currency and other goods seized from ousted Philippine president Ferdinand Marcos and his entourage when they landed in Hawaii in February.

U.S. District Court Judge Harold Fong of Honolulu said Customs had no right to detain the property. He added in a 25-page order that he had "grave reservations" about the agency's conduct and voiced suspicions that "certain employes and attorneys representing Customs have been less than candid with the court."

Fong said the Customs Service "has not seized the goods pursuant to any investigations into potential violations of U.S. law." And he rejected the agency's position that it could hold the property until it determined its rightful owner.

That position, the judge said, "flies in the face of nearly 200 years of customs law and practice."

The order also appeared to apply to the more than 2,000 pages of financial documents that were taken from Marcos when he landed in Honolulu Feb. 26 and were publicly released, over his protests, by a House Foreign Affairs subcommittee three weeks later.

The originals of those documents were subpoenaed by a federal grand jury and are in the custody of the Justice Department. Marcos has been given copies, but his efforts to keep them from becoming public were frustrated.

The U.S. attorney's office in Honolulu declined comment on yesterday's ruling, but Justice Department officials here were thought to be studying an appeal or motion to stay the release of the property.

Marcos and his party landed at Hickam Air Force Base in Honolulu with hundreds of pieces of jewelry initially appraised at more than $4.1 million. The valuables included a matched bracelet, earrings and brooch of sapphires, diamonds and rubies valued at $1.49 million.

Government sources said the value of the jewelry was raised to about $9 million in a reappraisal.

The inventory also showed that the Marcos group brought Philippine currency worth about $1.27 million and peso-denominated certificates of deposit worth about $2.27 million.

In Honolulu, where Marcos is living in a beachfront house, an aide, Arturo Aruiza, said last night that the deposed president is "very, very happy about the ruling."

Marcos, Aruiza reported, "said that the decision embraces what he has been saying all along -- that he believes in American justice."

Customs officials indicated they planned to sit tight for the weekend before deciding what to do.

In addition to his ruling, Fong issued a writ of mandamus directing Customs Commissioner William von Raab to release the disputed merchandise "upon payment of any assessed duties or upon posting of appropriate bond." He directed return of the currency and negotiable instruments without any conditions.

Customs Service spokesman Dennis Murphy said, however, that "our attorneys want to take a look at it Fong's ruling . We don't need to do anything hasty here."

Murphy also disputed the notion that the documents taken from Marcos and given worldwide publicity had been illegally seized.

"We turned them over in response to a lawfully issued subpoena," Murphy said of the agency's action in providing the records to the House subcommittee, headed by Rep. Stephen J. Solarz (D-N.Y.), as well as to a federal grand jury. As for the Customs Service's possession of the records in the first place, Murphy said: "I think if we conduct a border search and see documents that are questionable, we are entitled to copy them."

Customs officials did not copy the papers; they confiscated the originals.

The suit that led to the ruling was filed on Marcos' behalf March 13 by his son-in-law, Gregorio Araneta, and an aide, Ramon Azurin, as his attorneys-in-fact. Government lawyers defended the detention on the grounds that the action was authorized by executive authority and agreements with the Philippines, where the new government of Corazon Aquino was pressing for confiscation of the items.

Fong rejected the argument, saying the record before the court did not include "any agreement or executive order . . . which would have the binding force of law."

Beyond that, Fong said, "unfortunately, the executive branch has issued mixed signals on this matter." While White House chief of staff Donald T. Regan was classifying Marcos as "a distinguished foreign visitor" in order to get him Secret Service protection, the judge said, Undersecretary of State Michael H. Armacost was insisting that detention of the documents was consistent with U.S. support for the Aquino administration.

Fong criticized the Customs Service not only for a suspected lack of candor but for what he called an unsatisfactory "presentation of the law to this court."

"Although Customs contended that it was trying to determine the true ownership of the property," Fong said, "there was not a single document requested of Marcos or his agent which would allow Customs to conclusively determine ownership."

The judge added that two Cusoms officials had given "directly contrary statements" about the effort to determine true ownership. Fong said it was none of Customs' business anyway.

The ruling does not affect a lawsuit by the Central Bank of the Philippines seeking return of the currency on grounds it had been removed illegally. The bank's attorneys are expected to argue that the money should not be released until that case is settled.