CAIRO, NOV. 4 -- In an important step toward restoring close ties with Egypt, some of the Arab states along the Persian Gulf are discussing with Cairo a new defensive alliance to contain the military threat posed by Iran.

The issue, in the view of diplomatic observers, could split the Arab world at Sunday's meeting of Arab heads of state in Amman, Jordan.

Middle Eastern and western diplomats who have closely followed events leading up to the Arab summit conference say the alliance could lead to the deployment of Egyptian military advisers, trainers and possibly combat pilots and troops to defend Arab territory, particularly in Kuwait, which is vulnerable to spillover violence of the Iran-Iraq war.

Egyptian sources here stress that introduction of combat troops in the gulf region would be unlikely even if an alliance is formed, but a commitment to send troops in a purely defensive role to exposed countries such as Kuwait has been under discussion as a needed and credible deterrent to Iranian aggression.

Iran's Silkworm missile attacks on oil tankers and oil-loading facilities in Kuwaiti waters as well as its gunboat activity near joint Kuwaiti and Saudi Arabian offshore oilfields have sent the Arab states scrambling for a stronger Arab front to meet Iran's military threat.

"The gulf Arabs need a psychological counterweight in this war of nerves with Iran," an Egyptian government adviser said this week.

The Arab summit -- called after two unsuccessful attempts by Saudi Arabia to win support for an Arab-world break with Iran at foreign ministers' meetings in Tunis and Riyadh -- is expected to produce a confrontation between two of the Arab world's most bitter rivals, Syrian President Hafez Assad and Iraqi President Saddam Hussein. Assad, the Arab world's only open supporter of Ayatollah Ruhollah Khomeini's war effort against Iraq, will be seeking to head off Arab world sanctions against Iran, including an arms embargo under consideration in the U.N. Security Council. One western official here predicted that Assad will be on the defensive over his support for Iran, while trying to hold on to crucial Arab financial support that has kept Syria's tattered economy afloat.

Saddam Hussein, meanwhile, having lost the momentum to Iran on the battlefield during the last two winter offensives, needs an Arab world commitment to continue filling his war chest and mobilize international pressure -- particularly on the Soviet Union and China -- to bring Iran to the peace table on terms that will not humiliate his leadership.

A number of Middle East analysts predicted this week that the summit will produce few visible results and at best might come up with a formula that would move the stalled U.N. peace initiative forward. The Arab League, under whose auspices the summit has been called, requires unanimity for any action.

But the convening of this conference at a time of great division in the Arab world has created the potential for an Arab majority, led by Iraq and the larger Arab gulf states, to return Cairo to the Arab fold as a signal of Arab resolve against the expansion of Iran's revolutionary objectives in the region.

Some Arab and western officials said the growing violence in the gulf, where U.S. and western navies have deployed dozens of warships to protect international shipping, and the high stakes for both Assad and Saddam Hussein will charge the typically staid atmosphere of the summit hall in Jordan's capital.

In the competition for dominance at the summit between the Syrian and Iraqi rivals, a number of Egyptian and western officials here said this week that Egypt's strategic potential as a guarantor of Arab security could become an important sideshow.

Egypt has been a key arms supplier to Iraq, selling more than $2 billion in tanks, weaponry, munitions and spare parts since 1981 and sending tens of thousands of Egyptian workers and military "volunteers" to aid Iraq's war effort. But the Arab gulf states had depended on their own regional defense pact under the Gulf Cooperation Council for defensive military planning.

As the gulf war has grown more menacing, however, the council has been paralyzed by divisions among its member states -- Kuwait, Saudi Arabia, Bahrain, Qatar, the United Arab Emirates and Oman -- over how to deal with Iran.

In return for assuming a strategic role in the defense of Iraq's supporters along the Arab side of the gulf, Egypt is seeking economic investment and assistance, including the possible refinancing of its $4.5 billion military debt to the United States, by Arab gulf governments.

And, as the Arab leaders gather in Amman this weekend, several Arab ambassadors to Cairo have conveyed their governments' intentions to endorse a resolution that would either bring Egypt back into the Arab fold by a vote of the summit, or win recognition for bilateral restoration of relations after the summit.

"Quite a few Arab countries are at this time decided on restoring diplomatic relations with Egypt," said one confident Egyptian official this week. If it does not occur within the framework of the summit conference, two Foreign Ministry officials here said, "it would be a matter of weeks" afterward.

Most Arab League states cut diplomatic ties with Egypt in 1979, after the late Egyptian president Anwar Sadat signed a separate peace treaty with Israel following the Camp David accords. The only exceptions were Sudan, Somalia and Oman. Jordan was the first state to restore relations, in September 1984, followed by Djibouti this year. Morocco's King Hassan II has been reported ready to restore full diplomatic ties for some time as Egypt has become more deeply involved in coordinating Middle East peace initiatives.

Egyptian officials said they have received diplomatic signals from Kuwait and the Emirates that leaders in those countries are considering offering a motion at the summit calling for the return of Egypt to the Arab League and the restoration of diplomatic relations with member countries.

But Assad remains Egypt's most formidable critic over the Camp David accords, and his country holds the key to Egypt's fate at the summit.

Seldom, however, has Assad come to the summit table with a weaker bargaining hand. As one analyst here pointed out, Assad's support for Iran, his frustrated peace-making efforts in Lebanon, the deterioration of his military readiness and his unresolved economic crisis may soften his historic opposition to a formal Arab League reconciliation with Egypt.

Potentially, the most important arbiter of the summit could be Saudi Arabia, which announced this week that King Fahd will not attend the conference. Instead, it will be represented by Crown Prince Abdullah, who handles the kingdom's relations with Syria and who recently visited Washington for talks.

Some Middle East analysts believe that the Saudi royal family has been jolted out of its traditionally conservative and cautious role by this year's bloody confrontation with Iranian rioters in the holy city of Mecca and by increased Iranian military intimidation directed at Saudi oil installations and shipping.

The Saudis hold enormous financial leverage over Syria, where a $540 million annual stipend from Riyadh constitutes most of the cash in the Syrian treasury. Saudi wheat subsidies may determine whether there are bread lines in Syria this winter as the Syrian harvest falls 1 million tons short.

Multibillion-dollar Saudi funding has bolstered Iraq in the war and Saudi investments and grants throughout the Middle East have kept governments and potentially troublesome political movements in Riyadh's debt.

But Saudi Arabia has traditionally shown reluctance to lead an Arab initiative. Its strong stand in twice calling for a break with Iran since summer leads some analysts to conclude that either Fahd has decided to act more decisively or that a strong faction around the king, led by Defense Minister Prince Sultan, is influencing Saudi policy to a greater extent.

A determined Saudi Arabia would be a more forceful advocate for a gulf alliance with Egypt, officials here say.

Fahd's absence gives him more room to maneuver after the summit, according to analysts here. The crown prince will be able to take as strong a position on Iran and Syria as the Saudis deem necessary while preserving their king's options to shift course afterward.

But the political dynamics of an Arab summit, where there is no agenda and where leaders can weigh and change their tactics based on personal interplay and the ebb and flow of tearoom caucuses, are as impossible to predict as the shifting topography of the Arabian desert.Special correspondent Jane Friedman contributed to this report.