TEL AVIV, Israel (AP) _ Government officials declined comment Thursday on reports that Israeli arms and spare parts had been shipped to Iran as part of a deal to secure release of American hostages held in Lebanon.

''All that we have heard from the press is a matter of speculation,'' said Aviv Shir-On, a Foreign Ministry spokesman. ''We do not respond to speculation in the press.''

But some Israelis who study Israel-Iranian relations say Israeli light weapons and spare parts could be reaching Iran.

Joseph Alpher, deputy head for the Jaffee Center for Strategic Studies, said Israel may now be overhauling Iranian fighter jet engines in third countries and selling Iran spare parts such as tires for U.S.-made F-4 planes. He declined to elaborate.

One student of Israeli-Iranian affairs said any sale of arms by Israel could not be made without U.S. permission.

''Israel would not risk its ties with the United States for such monkey business,'' said Shmuel Segev, author of a book on Iranian-Israeli ties during the rule of the late Shah Mohammad Reza Pahlavi.

''There's always the possibility that Israeli weapons sold to a third country, such as Latin American states, have found their way to Iran,'' Segev told The Associated Press.

But Alpher and Segev, along with others, discounted the idea of massive Israeli arms sales to Iran.

''If there were such sales, there's no evidence of them in Iran. Where are all those tanks, planes and missiles?'' Alpher said in an interview.

Foreign reports said the United States used Israel as a conduit to ship weapons to Tehran in exchange for the freedom of hostages held by Shiite Moslem groups in Lebanon with ties to Iran.

In Washington, one source said the United States won release of three hostages in the past 14 months by helping arrange shipments of spare parts from Israel to Iran.

In addition, Israel radio reported that Israeli officials offered advice to former U.S. national security adviser Robert McFarlane about how to negotiate with Iran for the release of hostages.

Foreign Ministry officials called all the reports baseless. Defense Ministry officials said Israel's policy was not to talk about its weapons deals.

But there have been persistent reports that Israel sent small shipments of weapons to Iran as recently as this year. In 1982 former Defense Minister Ariel Sharon said the United States knew about a $27 million Israeli weapons sale to Iran.

Specialists in Israeli relations with Iran note that Israel would have reasons for selling small weapons to Iran, despite that country's anti-Israel rhetoric and Israel's war in south Lebanon against pro-Iranian Shiite Moslems. They said:

-Israel would have trouble saying no to a request from its major ally and arms supplier, the United States, to help secure the release of the hostages held in Lebanon by Shiite Moslems.

-Israel is also concerned about Iran's Jewish community, estimated at about 25,000 people, which has suffered persecution. Some reports say Israeli weapons have been exchanged for permission for Iranian Jews to emigrate.

In the days of the Shah, links between Jerusalem and Tehran were close. They began with a 1964 shipment of Uzi submachine guns.

Such deals were halted with the overthrow of the Shah in 1979 but reportedly renewed soon after the 1980 outbreak of the Persian Gulf war and the 1979 U.S. ban on arms sales.

Analysts have suggested that Israel signed deals with the Ayatollah Ruhollah Khomeini in an effort to obtain exit permits for about 70,000 Iranian Jews.