WASHINGTON (AP) _ Texas billionare H. Ross Perot provided Lt. Col. Oliver North with $300,000 in two cash installments to help pay for an operation using U.S. narcotics agents to find American hostages in hopes of rescuing them, Sen. Paul S. Trible Jr., R-Va., said Friday.

Records of the U.S. Drug Enforcement Administration indicate that North ''provided $270,000 in cash to further this operation,'' Trible said in an interview. But he added that it is not clear whether Perot was the source of that money.

Trible, a member of the Senate Iran-Contra investigating committee, said on Thursday that the Central Intelligence Agency had also contributed $50,000 to keep the project going.

Trible said on Friday that CIA agents attended some early meetings to discuss the project but that it was essentially run by drug agents acting under North's direction.

''North was in charge of the operation,'' Trible said. ''The DEA agents reported to North. There were two agents involved. They spent over 90 percent of their time on this. The operation began in January 1985 and continued through the summer of 1986.''

''There were payments made for intelligence and other undertakings,'' Trible said. ''We know how most of the money was expended.''

Former National Security Adviser Robert McFarlane testified Thursday that he had conferred with Reagan about a bribe-and-ransom program, that ''the legalities and so forth were handled by the attorney general and it was a matter of consensus between the attorney general, the president, myself.''

He said Reagan had approved the program ''in writing and (it) probably is a matter of record.''

Asked about that on Friday, Reagan said, ''I'm having some trouble remembering that, but then I want to tell you that there were so many things going on and so many reports, and some of this was during the time that I was laid up in the hospital'' for cancer surgery in July 1985.

''I don't recall ever anything being suggested in the line of ransom.''

Reagan said the administration was constantly exploring possible ways to free the hostages, and he added, ''It's possible that what we're talking about was use of money to pay people and hire individuals who could effect a rescue of our people there. And, I've never thought of that as ransom.''

Trible said that during the course of the operation he was describing, ''there was a large cash payment to someone in return for information about the health and whereabouts of the hostages.''

He said he does not know the total of the payment, the identity of the person to whom it was made or the precise nature of the intelligence received.

''That was the only real enterprise that was involved,'' he said. ''A lot of time was invested to secure information about the whereabouts of the hostages.''

Trible also provided new details about a larger cache of money made available by Perot last year to ransom the five Americans then being held hostage in Lebanon.

Previous accounts have indicated Perot put up a $2 million cash ransom and sent it to Cyprus by courier at North's request. After a five-day wait, the deal fell through.

After the initial disclosure that he had put up the cash for a hostage ransom attempt, Perot told reporters he assumed the plan had been approved by higher authority than North.

White House officials said at the time that the ransom plan was not known at the National Security Council and ''certainly was not authorized.''

Trible said the understanding was that after the ransom had been paid and the hostages released, they would be taken from Lebanon by a fishing boat which would meet off the Lebanese coast with a larger vessel.

Trible said he has not been able to learn the identity of the vessel but assumes it was the Danish freighter ''Erria,'' identified in the congressional hearings as having been puchased by associates of retired Air Force Maj. Gen. Richard V. Secord for use in privately funded clandestine operations.

''There were never any arrangements worked out for paying ransom and therefore never a call for the vessel,'' Trible said.

The senator said the ship to be used to pick up the hostages, if they were successfully ransomed, was purchased by investor-consultant Thomas Clines, a Secord associate.

Clines, a CIA official from 1949 to 1978, reportedly had been involved in shipping arms and ammunition to the the Nicaraguan Contra rebels.

Trible said the ship had a Danish captain who said he had previously been involved in shipping arms to Central America.

Senate investigators are seeking a full accounting of the ransom effort from the DEA and the CIA, Trible said.

''There was clearly an obligation to notify Congress'' once the CIA became involved, Trible said. ''And Congress was not notified.''

''This is a classic example,'' he said, noting that official U.S. policy at the time was not to negotiate with terrorists and not to pay ransom for hostages.

''If there had been consultation with Congress, someone would have said, 'Hey, this is contrary to our stated policy and everything we are doing around the world,''' Trible said.