A top economic official of the Iranian government said yesterday that President Carter, using court orders, legal and legislative precedents and his own executive powers, can lawfully meet Iran's four conditions for release of the hostages in Tehran.

White House and State Department officials were awaiting clarification of the complex details of these conditions, but a high Iranian official who took part in drafting them offered a further explanation to The Washington Post in a telephone interview from Tehran.

Unfreezing of Iran's assets and making them available for Iranian government use could be accomplished, the official said, by an executive order from the president and reliance on a court order issued last month in New York by a U.S. District Court judge, Kevin I. Duffy.

Some attorneys involved in claims for American companies, however, said yesterday that it might not be so simple. There are legitimate legal questions about how much authority the president has now that many of the claims cases are before American courts, they said. And Carter said in his statement on the conditions for release last night: "Any action taken by our government will be in full accordance with our laws and with our Constitution."

The Iranian assets were frozen by presidential order last Nov. 14 in response to Iran's seizure of American Embassy personnel, partly to prevent Iran from withdrawing the billions in deposits from U.S. banks. Since then, more than 300 banks, corporations and individuals have filed lawsuits against the frozen assets, seeking payment for holdings nationalized by Iran, lost contracts and defaulted loans that came about in the wake of the Iranian revolution.

When the more than $8 billion in Iranian government assets was frozen (Iranian officials put the figure at $14 billion), these banks and corporations went into court and sought legal orders, called attachments, that would hold the money there until the individual claims were settled.

Ninety-six claim cases representing some $3 billion are before Judge Duffy. Last month, over the objections of the U.S. government and Iranian government lawyers, Duffy certified the attachments on that amount of money.

In his order, however, Duffy wrote that the only reason the assets could be attached was that they were frozen by the U.S. government and were no longer the property of the Iranian government. If the U.S. freeze were removed, the judge declared, the assets would again belong to the Tehran government and, under the legal doctrine of sovereign immunity, would not be subject to claims by individuals or corporations.

"The Duffy order accepted the immunity of the Iranian central bank funds," the Iranian official said. He added that, if any claimant wants to go back into court after the freeze is lifted and reinstitute an attachment, that action would endanger the release of the hostages. For any bank or company, he said, it would be "politically unwise."

The Iranian official argued that the commercial claimants were taking advantage of the hostages "to get money they might not deserve." He added that Iran would be willing to meet any claim in court and pay those where courts found them deserving.

The freeze situation has been further complicated by the actions of several major American banks, led by the Chase Manhattan Bank of New York, which had conducted extensive financial affairs with the shah and his government. Chase Manhattan was the lead bank on a $500 million loan to the shah's government that was kept current even after the Ayatollah Ruhollah Khomeini regime took power. When the Iranian assets were frozen last fall, however, the funds on hand in Iran's accounts at Chase branches were frozen and could not be used to pay interest on the loan. Chase immediately called the loan in default and that set off a series of other Iran loan defaults, because of a banking agreement then in effect.

Under Carter's freeze order, the banks were given the right to take Iranian deposits they held and use them to "set off" the defaulted loans, as bankers call it. These banks could still argue for their position if the president acts to free the Iranian assets.

A spokesman for Chase said yesterday the bank is "hopeful . . . that a meaningful breakthrough be achieved with regard to the American hostages." But, concerning the assets, he said "we strongly believe that the U.S. government and its judicial system will respect the legitimate claims of Americans. . . ."

The Iranian banking official said that, while it would be difficult, the United States should restore the foreign assets to the status of last Nov. 13, before the freeze and before the defaulted loans. If necessary, he said, an international banking commission could be established to straighten out the situation.

Lawyers for major U.S. banks and corporations had no official comment yesterday. One, asking that his name not be used, said a lifting of the freeze by Carter would set off a race for the courthouse. He added that the Iranian assessment of the Duffy order might hold up. Others, however, disagreed.

The Iranian official stressed his view that once his government again has legal control over its now-frozen assets, Tehran officials would not make any sudden effort to remove the billions from the United States, since such an action could cause economic dislocation. He noted, for example, that about $1.2 billion of the Iranian assets are in U.S. Treasury bills and selling them all at once would disrupt money markets.

On the question of confiscating and returning the late shah's private wealth to the Iranian government, the Iranian official outlined a three-step procedure he said President Carter could take to satisfy that condition.

The first step, he said, would require the government in Washington to acknowledge the right of the Iranian government to nationalize the holdings of the late shah and his family. The second step would be for Washington to accept the nationalization as legally valid in Iran and elsewhere, including the United States. Finally, he said, "The U.S. president could issue an order to transfer those nationalized assets" to the Tehran regime.

He acknowledged that the shah's family undoubtedly would challenge the transfer, but he said the actions would put the Iranian government in a better legal position to meet court challenges.

The Iranian official said there are also historic precedents for the condition demanding that the U.S. government take responsibility for any legal claims for damages that might be filed against Iran by the hostages or their families. In fact, several damage suits suits have already been filed in behalf of hostages.

In the past, he said, the United States has played a similar role of intermediary and even paid off claims involving the Cambodians, North Koreans and the Soviet Union. However, one U.S. official who is expert in foreign claims said he knows of no precedent comparable to the present situation. The cases cited by the Iranian official are not applicable, he said.

Removal of all judgments on claims by U.S. corporations and individuals against Iran seeking repayment for their losses from nationalization, the defaulting of contracts or seizure of equipment posed a problem "but could be done," the Iranian official said. He said the International Emergency Economic Powers Act gives the president legal authority to set aside court orders in these circumstances.