The head of Iran's central bank said yesterday that one condition for release of the 52 U.S. hostages is "a guarantee" that Iran will immediately get back at least some of its $8 billion in assets frozen by the U.S. government last November.

The guarantee could come either "by direct word" of the United States or through "a third-party guarantor," he said.

Ali Reza Nobari, Iran's top banking official and a close political associate of President Abol Hassan Bani-Sadr, said yesterday in a telephone interview from Tehran that he was aware that Iran's money could still be held in U.S. banks by court orders if President Carter's freeze were lifted. But he added, "Carter has the right to bypass the courts" and make some of the funds available.

Ayatollah Ruhollah Khomeini last month set his conditions for release of the hostages, including "the freeing of all our investments" and the cancellation of U.S. claims against Iran.

Nobari said the Iranian parliament would be presented with the conditions today and told "whether they have been fulfilled" by the United States.

The "guarantee for us that all the money will be freed . . . and procedures for carrying it out," Nobari said, are being negotiated, but he declined to say how that was being done. In Washington, government sources said that "intermediaries" were presenting various proposals on how to handle the assets problem, but officials were uncertain which plan represented what the Iranians really want.

Nobari said Iran wants a clear understanding that when the hostages are freed, "there can be movement of some money . . . and what was paid for should be returned to us." The latter is a reference to the $550 million worth of military equipment that was already ordered and paid for by the Iranian government before the Nov. 14 freeze went into effect.

Informed officials in Washington said yesterday that although there are complications involved in freeing the assets, a substantial sum could be released "by a stroke of the president's pen." Sources cautioned, however, that Nobari personally, is not considered to be in the small group of men who have individual power in Iran today and it is unclear whether his views represent the position of the government or the legislature.

Carter froze Iran's assets 10 days after the hostages were seized. The move was in response to pressure from the country to do something, short of military retaliation.

More than $2 billion was in U.S. government securities and gold held by the Federal Reserve Bank of New York. Another $1 billion was in deposits at American commercial banks in the United States and $4 billion was held by overseas branches and subsidiaries of U.S. banks. The last $1 billion was split, with about $400 million held by the U.S. Treasury to pay for Iran's Pentagon purchases and about $600 million in the hands of private U.S. companies from which the Iranians were buying goods or services.

In the 11 months since the freeze was imposed, the Iranian assets have been subjected to a variety of banking and legal moves that now make it extremely difficult to return them to the Khomeini regime.

The freeze precipitated, for example, a controversial action by the Chase Manhattan Bank. The Chase was lead bank on a $500 million loan originally made to the government of the shah. With the Khomeini regime's money frozen, the funds on hand in Iran's accounts at Chase branches could not be used to pay interest on the loan and Chase declared the loan in default. A complicated series of banking agreements then led to all Iran's loans from U.S. banks being declared in default.

The banks then took advantage of a section of President Carter's order and used the frozen Iranian funds they held to pay off the "defaulted" loans. According to the Associated Press, Chase, for example, deducted $366 million from Iranian deposits, and last week its chairman, David Rockefeller, told the news service that the bank no longer had any Iranian credits on its books.

Along with banks, companies and individuals have gone into federal courts claiming the Iranian government either owed them money or had seized their equipment in Iran without compensation.

According to one lawyer working on the Iranian assets situation, there have been about 265 separate legal actions filed, with claims amounting overall to some $6 billion dollars. Under U.S. law, a claimant seeks a court order against an Iranian asset that would cover the amount he hopes to recover should he prevail in court.

When a judge approves such an order, called an attachment, the asset covered cannot be removed until the legal claim is resolved.

The Iranian situation has been complicated by the fact that all the assets being attached are bank accounts, securities and gold belonging to the Iranian government. Under the so-called doctrine of sovereign immunity, American companies, banks or individuals cannot sue a sovereign country, such as Iran, nor attach its property.

Ninety-six claims cases against Iran have been consolidated in the U.S. District Court in New York, and on Sept. 26, Judge Kevin T. Duffy, rejecting government pleas for delay, certified the attachment of about $3 billion of Iranian assets.

Duffy ruled that the assets could be attached because they were frozen and thus did not belong to the Iranian government. He suggested, however, that should the freeze be lifted, the assets would again belong to the Khomeini regime and perhaps not be subject to attachment because of the doctrine of sovereign immunity. Duffy's ruling caused concern in Washington since both Treasury Secretary G. William Miller and Undersecretary of State Warren Christopher made in camera representations to the judge attempting to get him to delay action.

Some of the claimants are fearful that if the freeze is lifted, the U.S. government may support the concept of sovereign immunity and leave the claimants without any way to get their money back.

Nobari said yesterday that he believes President Carter could declare the assets situation returned to the status of Nov. 13, 1979 -- the day before the freeze. Washington sources said Carter could "vest" or take title to the Iranian assets after lifting the freeze and return them to the Tehran government. But the president cannot divest the courts of their jurisdiction and thus the government would have to become a party to the claims cases.