There is "a good possibility" that Saudi Arabia, the world's leading oil exporter, will continue to produce oil at a rate above its 8.5 million-barrel-a-day ceiling, Saudi oil minister Sheik Ahmed Zaki Yamani said yesterday.

The Saudis' continued procuction of oil at their current 9.5 million-barrel-a-day level would ease the pressure on world oil markets and help restrain prices.

"The decision will be made in December," Yamani said, adding, "we might renew our decision to have a higher rate of production."

Yamani further said that Saudi Arabia would oppose a price increase at the oil cartel's December meeting if the western countries cut back oil consumption.

Earlier this month, after personal entreaties from President Carter, Saudi Crown Prince Fahd announced that the Riydah government would produce 9.5 million barrels a day through the end of the year.

Amani's statement came on the heels of a new round of price increases and production cutbacks announced last week by other members of the Organization of Petroleum exporting Countries.

Yesterday, Libya, America's third largest supplier of oil, and Iran announced price boosts of $2.77 and $2.87 per barrel respectively, thereby exceeding OPEC's official ceiling price of $23.50. Saudi Arabia sells its oil at $18 a barrel, the lowest price charged by any of the cartel members.

Last week, Kuwait and Mexico -- though the latter is not a member of OPEC -- notified customers they were raising oil prices by $2 a barrel or more.

Energy Department and oil industry sources yesterday said they expect Nigeria and Algeria, leading North African suppliers, to raise their prices soon in line with the 11 percent increase announced by Libya and Iran.

John Lichtblau, an international oil analyst, said that if North Sea Producers and the rest of the OPEC members, except Saudi Arabia, raise prices $2 or more a barrel, U.S. gas and fuel prices will increase by 2.5 or 3 cents a gallon.

During a lunch meeting at The Washington Post, Amani stressed that Riyadh will not produce oil above its 8.5 million-barrel-a-day ceiling if there is a surplus in the world oil market. In recent weeks, senior Saudi officials have been saying that, barring further political disturbances in Iran or another OPEC state, there will be a glut next year because of reduced oil demands stemming from the recession in the West.

Later in the 1980s, as western economies begin to expand again, the Saudis say they expect a severe oil shortage.

Yesterday, Yamani again recited his long-standing plea to western industrial countries to cut back oil imports.

"If you reduce consumption, I can guarantee there will be no price increase," he said, adding that the Sandis "will call for moderation" at the December OPEC meeting in Caracas.

Asked how to hold down prices on the spot market -- currently at $40 a barrel or more in ROTTERDAM -- amani said, "Stop the companies from entering the spot market."

Yamani is expected to take up these questions during meetings here with Treasury Secretary G. William Miller and Energy Secretary Charles Duncan.

Asked whether OPEC is considering dropping the dollar as its way to price oil in exchange for a so-called basket of currencies, Yamani said, "No matter what the OPEC decision is regarding a basket of currencies, Saudi Arabia will always accept dollars." He added, "We hope that the dollar will continue to appreciate."

While stopping short of publicly linking oil and Mideast policy, the Saudis have continued to say privately that the two issues are bound.

In the near term, the major uncertainty regarding the world oil market continues to be iran. The Saudis have suggested that if Iran continues to produce between 3.2 million and 3.7 million barrels of oil a day, there will be a surplus next year and possibly a price reduction.

The Saudis are understood to disagree with recent reports that Ayatollah Khomeini's government has sharply reduced oil exports by as much as 1 million barrels a day.