New allegations surfaced yesterday involving an unproven story that senior officials of the 1980 Reagan campaign secretly agreed to allow the shipment of U.S. arms to Iran if the Tehran government waited until after the November election to release American hostages it was holding.

The hostages were released moments after Ronald Reagan's 1981 inauguration, and within the next few months, some U.S. military spare parts and other military equipment reportedly went to Iran through Israel, despite an American arms embargo against Iran. This chain of events has helped keep alive speculation that a secret deal existed between Reagan campaign officials and Iranian authorities.

The new allegations were contained yesterday in a New York Times op-ed article written by Gary Sick, a Middle East specialist who worked on the Iranian hostage crisis as a member of the Carter administration's National Security Council staff. The case is the subject of a documentary to be broadcast tonight on the PBS "Frontline" series.

Sick's account, the product of two years of research, alleged that in late July 1980 a pair of previously undisclosed meetings took place in Madrid between the late William J. Casey, then Reagan's campaign manager and subsequently CIA director, and an Iranian middleman named Mahdi Karrubi, now speaker of the Iranian parliament. Reagan won the Republican nomination on July 17.

At subsequent meetings in Paris in October 1980, allegedly attended by Casey, Israeli representatives and high-level Iranian officials, the Iranians agreed not to release the hostages before the election, Sick wrote.

Sick repeated previous allegations that then-vice presidential candidate George Bush attended one of the Paris meetings. That has been steadfastly denied.

"Our position on all of this is the same as it always has been, that there is nothing to it. And Vice President Bush never even went to Paris," White House press secretary Marlin Fitzwater said yesterday.

Sick said his principal source for the occurrence of the two meetings in Madrid was businessman Jamshid Hashemi, who along with his late brother, Cyrus, had contacts in Iranian revolutionary circles.

In 1984, Cyrus Hashemi was indicted on charges of running an illegal operation to export weapons and military spare parts during the 1980 hostage crisis, a fact that was not mentioned in Sick's article. Senior Carter administration officials, recalling that Hashemi had approached them in early 1980, have suggested he was an arms dealer looking for a way around the U.S. embargo.

In 1985, Cyrus Hashemi, who was still under indictment, used a friend of Casey's to try to get the CIA director interested in providing arms to Iran in exchange for U.S. hostages held in Lebanon; in return, Hashemi was seeking to have the charges against him dropped, according to his attorney at the time.

Former national security adviser Richard V. Allen, chief foreign policy adviser to Reagan during the 1980 campaign, yesterday described the Sick allegations as completely untrue.

Allen has previously described meeting in August or September 1980 with someone claiming to be an Iranian middleman at the suggestion of Robert C. McFarlane, who was then working for the Senate Armed Services Committee. This individual, Allen said, wanted to arrange for the release of the American hostages "to the Reagan forces." But Allen said that after 15 minutes, he got up and left.

After the election, Allen continued, he was approached at a social event by Morris Amitay, who was director of the American-Israel Public Affairs Committee until December 1980. Amitay reportedly told Allen that in return for Iranian Jews being allowed to emigrate to Israel, Israel wanted to send brake systems and wheel assemblies for F-4 fighter jets to the Tehran government.

Allen reported saying, "Tell your friends I heard what you said." But he maintains he was indicating neither approval nor disapproval.

In fact, the hostage release was negotiated by the Carter administration after the election during tough and drawn-out talks with Iranian representatives. The talks almost fell through at the last minute. The Carter deal did not include the release of any U.S. arms to Iran, although Iran was making the case that some had been paid for and should be shipped.