Imelda Marcos, the wife of the Philippine president, hosted three meetings at her New York town house last year during which she discussed the financial status of $350 million worth of Manhattan real estate, a New York investment banker told a congressional hearing yesterday.

Barry Knox, who monitored or arranged loans for the buildings, said two of the people present had told him repeatedly that Imelda Marcos was the owner of the properties. However, he said, he remained unsure because he had received conflicting stories.

"At the last meeting she conducted herself more like an owner," Knox said.

The testimony before the House Foreign Affairs subcommittee on Asian and Pacific affairs was the first in four hearings to link Imelda Marcos directly to high-rise office buildings and glittering shopping centers purchased by offshore holding companies over the last five years.

The subcommittee chairman, Rep. Stephen J. Solarz (D-N.Y.), said the investments represent "the tip of the iceberg" of billions of dollars shipped overseas by the Marcoses and their associates since 1979.

Solarz said Knox's testimony had been "extraordinarily helpful" in demonstrating that the denials by Philippine President Ferdinand Marcos and his wife of U.S. property ownership are "about as accurate as Mr. Marcos' assurances about his war record." He referred to reports that the U.S. Army rejected Marcos' claims to have run a major anti-Japanese guerrilla operation during World War II.

Rep. Gerald B. Solomon (R-N.Y.) called the hearings "disgusting" and "a witch hunt" designed to influence the outcome of presidential elections Feb. 7 in which Marcos is seeking reelection.

Knox said all three meetings took place at Imelda Marcos' town house on East 66th Street in Manhattan. The first, in February 1984, concerned the need for $30 million to cover additional costs in developing the Herald Center shopping mall at 34th Street and Avenue of the Americas, and involved half a dozen people, he said. All of those present were familiar with the situation and were there to brief Imelda Marcos, Knox said.

At one point, Imelda Marcos stood up and said, "I don't have $30 million," Knox testified.

The second and third meetings in fall 1984 involved discussions of all four properties. Imelda Marcos turned to a Filipino banker during the third meeting and asked whether there was an additional $10 million available to invest in an office building at 40 Wall St., Knox said.

Knox said he acted as an agent in the deals for Glyceria Tantoco, owner of a Philippine department store chain and wife of the Philippine ambassador to the Vatican. "On several occasions Mrs. Tantoco mentioned to me" that Imelda Marcos owned the four properties, Knox said.

"But she Tantoco also mentioned to me that she was the owner, and then that she was the head of a group that owned it," he said. Tantoco "acted very much like an owner," often making snap decisions over millions of dollars, he added.

Knox said he worked closely in keeping track of the properties' tangled mortgage and income status with Joseph and Ralph Bernstein, two New York attorneys whom the Foreign Affairs Committee has cited for contempt of Congress for refusing to testify in the matter.

Joseph Bernstein "always said that Mrs. Marcos owned" the Crown building, Knox said. "We treated the three other properties as one," he added.

In a related development, Senate Foreign Relations Committee Chairman Richard G. Lugar (R-Ind.) is expected to forgo his reservations over possible fraud during the Philippine presidential election and recommend today that President Reagan name an official delegation of observers to the balloting.

Congressional sources said Lugar, who would probably head the delegation, would stress that the 40-member group should be a symbol of U.S. support for the democratic process and for elements seeking reform in the Philippines, rather than to help certify election results.

The Philippines' acting foreign minister, Pacifico Castro, on a three-day visit here, met yesterday with national security affairs adviser of State George P. Shultz. He reportedly gave Shultz a formal invitation from Marcos for Reagan to send the observers, and Reagan is expected to respond today.