Israel, says James E. Akins, former United States ambassador to Saudi Arabia, has stepped up its military assistance to Iran. Back from a trip to the Persian Gulf countries, he says the American-operated AWACS radar planes based in the Saudi capital of Riyadh have been tracking Israeli planes flying north over Lebanon and Syria to south Turkey, where they lose track of them. But Iraqi radar has picked up aircraft moving from there to Iran.
Mr. Akins assumes the ''daily flights'' are carrying spare parts and other military supplies. ''You can be sure they are not sending cut flowers,'' he said in a telephone interview.
A State Department spokesman, however, says that although he ''cannot categorically deny'' Akins's charges, Israel has stated it has stopped supplying equipment to Iran, and the State Department has no evidence to the contrary.
Further, he held that the AWACS planes were flying patterns that would not provide information on Israeli flights. Still, the spokesman admitted that Mr. Akins has good Middle East information sources.
Akins maintains that the Israelis are not telling the truth about their help to Iran. Akins, now a Washington-based energy consultant, also believes that the Iranians have obtained new weapons that could be ''quite effective'' in the tanker shoot now under way in the Persian Gulf. He would not elaborate on this statement. Moreover, he suspects the Iranian Air Force is in better shape than many press stories would indicate.
Like some other oil experts, Akins has become more pessimistic in recent days about the impact of the Iran-Iraq war on Arab as well as Iranian oil shipments from the Gulf.
For the time being, he figures that the surplus production capacity of the Organization of Petroleum Exporting Countries (OPEC) outside the Gulf leaves the world in ''a reasonably comfortable position'' for oil supplies.
But Morris A. Adelman, an oil economist at the Massachusetts Institute of Technology, notes that there was no real shortage of oil in 1979, when prices of crude tripled, and only an ''insignificant'' shortage of oil in 1973-74, when OPEC quadrupled the price of oil.
''All you need,'' he warned, ''is for some of the trade to get nervous enough to start buying for inventory.'' These worried oil consumers can push up crude spot prices. They are joined by speculators hoping to make quick money on rising prices. ''The needy are joined by the greedy,'' Mr. Adelman said. ''I think there is a little too much complacency,'' he concluded.
Should Gulf oil going through the Strait of Hormuz be cut off completely - which is considered unlikely - the world would lose some 9 million barrels per day (the flow in the first quarter of the year), or about 20 percent of consumption. At the moment, much of the flow from Iran (about 1.7-1.8 million barrels daily) has been stopped by the danger of Iraqi bombing.
So far, Iranian attacks on shipping have slowed - but not stopped - exports of Arab oil. Much of the lost production could be replaced by surplus capacity in other countries or out of the reserves of the United States, Japan, or Western Europe. Some oil users could also switch to alternative fuels, such as natural gas or coal.
Mr. Akins is concerned about calls from some congressmen that oil pumped from the 400 million-barrel US Strategic Petroleum Reserve be used only in the United States in an emergency. They argue that the US imports only 3 percent of its oil from the Gulf and would thus be sitting pretty in the event of a cutoff.
But Akins sees two mistakes in this stand.
First, in addition to oil shipped directly from the Gulf, the US imports Gulf oil indirectly from refineries in the Netherlands Antilles (235,000 barrels daily in the first quarter) and the Virgin Islands (204,000 barrels daily). Added up, those imports almost equal those from Venezuela, the third-largest supplier of crude to the US, after Mexico and Canada.
Second, to make use of the oil reserve exclusively for the US would be a formula for the end of NATO, he said. The International Energy Association, set up by an executive agreement among the industrial nations, calls for sharing oil in the event of a world shortage.
This is not an international treaty, as Akins urged when he was head of the Office of Fuel and Energy at the State Department; so sharing is not a legal requirement. But it is a ''moral obligation,'' Akins said. He held that all the allies should draw down their stocks together in the event of an oil crisis.
MIT's Professor Adelman regards the world's oil supply as one big pool. Should the United States hoard its strategic reserves to itself, other nations will be forced to bid away oil from Mexico, Venezuela, Canada, or other major suppliers to the US, ''if push comes to shove.''
The solution Mr. Adelman recommends is for the United States to make its reserves available at spot prices for delivery today, or at an auction price for later delivery. But buyers would have to put cash down. This would discourage speculators bidding on slim margins.
''You are not needing to guard against a shortage, but a panic,'' he noted. Assured supply would calm fears.