Iran's revolutionary government said yesterday it would sharply curtail future oil exports, raising new questions about continuing upward pressure on world oil prices.

In the first announcement of the new government's production targets, Hassan Nazih, head of Iran's national oil company, said it would hold exports to 3 million barrels a day, roughly half the level exported under the shah.

Industry and U.S. government officials reacted favorably to the first signs of stability in Iran's production, but one senior Energy Department official said, "It would be a mistake to say the crisis in Iran is receding."

The major concern of most importing nations now is not the threat of a severe oil shortage but the impact of rising prices.

In other energy developments yesterday:

Energy Secretary James R. Schlesinger told the National Petroleum Council that the outlook for oil supplies next winter ranges from a "tight market" to "very severe."

Senior administration officials said President Carter will make his long-awaited energy speech within two weeks. The speech likely will be followed by a message to Congress and new legislative proposals, unless Carter rules this out, according to one high official. Roughly 40 items are now being discussed by a sub-cabinet group headed by Stuart E. Eizenstat, Carter's senior domestic policy adviser. "A consensus is forming," the official said.

The speech will include measures to deal with the Iranian oil shortage, proposals on crude oil price controls, which can be lifted in June, solar and nuclear energy initiatives, and additional incentives for production such as allowing Alaskan oil exports.

Industry and administration sources also say that the Energy Depatment is weighing proposals to eliminate the license fees, or tariffs, on imported oil and refined products, to ease pressure on prices.

Assistant Treasury Secretary C. Fred Bergsten said the United States will spend more than $50 billion on imported oil during 1979, a 20 percent increase. Elsewhere in the administration, top officials are saying that the outflow will rise still higher, at least a few billion dollars more, because the Organization of Petroleum Exporting Countries is expected to raise prices still higher at its March 26 meeting in Geneva. This would give official sanction to the $1.20 surcharge that eight of the cartel's 13 members have imposed on the official price of about $13.50 a barrel.

The International Air Transport Association said that about 80 of its member airlines would meet in Geneva later this month to discuss fare increases because of sharply higher jet fuel prices.

Allegheny Airlines joined TWA, United, Eastern, Delta, Continental, Piedmont and other major U.S. air carriers, announcing it will begin cutting its flights as early as next week because of fuel shortages.

Others who announced cutbacks yesterday include Lufthansa and Flying Tiger, one of the nation's largest air freight carriers.

In Tehran, Nazih told reporters that Iran will press the other OPEC countries to adopt the Persian Gulf state's $18-a-barrel price demands. "We have always been a militant party in OPEC and will continue to be so." Nazih said.

He also said that the National Iranian Oil Co. would need "very few experts on the whole" to boost oil production. Over recent weeks NIOC has asked the western oil consortium's oil service company to return 119 of its more than 500 expatriate oil technicians and engineers to help restore production. The foreign workers left Iran last December.

Declaring that Iran's production policy "will be dictated only by Iran's national interest," Nazih went on to say that "in our view, prices set and announced by OPEC are regarded as floor prices and whenever possible we shall sell at prices higher than OPEC prices."

State Department and American intelligence analysts have said that Iran must produce a minimum of 3.6 million barrels a day to meet its internal needs and salary increases announced by the Hah before he was dethroned.

Over the last week the State Department dispatched cables to major industrial countries urging them to dissuade companies from buying oil at the high spot prices of $18 to $20 a barrel demanded by NIOC, according to senior officials.

Schlesinger and State Department officials hope they can forestall sales of oil in the spot market, now running $3 to $5 and more above the official price, to prevent OPEC from raising its official price to that level.

Meanwhile, State Department and oil industry officials said that reports that Libya, one of the cartel's key producers, has cut back its oil production are incorrect. Instead they say that like other producers such as Abu Dhabi and Iraq, Libya has reduced the amount of oil it sells to the major oil companies in order to increase its sales at premium prices.