Prince Mohamed Al-Faisal said here today that he hopes to have an 100 million-ton Antarctic iceberg moored off the coast of Saudi Arabia and producing fresh water for his oil-rich but arid land within three to five years.

He said one estimate of the cost of the necessary research and engineering to move the first iceberg was $100 million.

The prince spoke at the concluding press conference of the first International Conference on Iceberg Utilization held at Iowa State University here this week.

Participants at the conference have likened it to the conference called 100 years ago in Paris, France by Ferdinand de Lesseps which led to the construction of the Panama Canal.

Faisal put up $50,000 to get the conference going to explore the feasibility of towing icebergs from the antarctic provide fresh water for his desert nation. The conference was held in Iowa because a friend of the prince, Dr. Abdo Husseiny, is a member of the nuclear engineering staff at Iowa State and persuaded the prince that Iowa State would be a good location.

"That whole feeling that has come out of this conference is that the project is feasible," the Prince said. "That has been proven to me."

The next step, he said, will be to analyze the results and set up a permanent body of experts to carry on the work.

Referring to the $100 million cost estimate, the prince said it "possibly could be much, much less if get a breakthrough."

As to further financing, he said that if the initial project proves feasible, "we will get all the financing we need."

The prince indicated that the King Faisal Foundation in Saudi Arabia, which is supported by oil money, might serve as the central research organization for the project.

Experts have said that the water shortage in Saudi Arabia is critical and that the nation will not have enough to meet even drinking water needs by 1985 unless new sources are found.

Faisal acknowledged that there were less exotic ways of meeting his nation's needs, including desalinization, but he said he felt "icebergs will be better in the long run [because] they are more abundant . . . cheaper, and [have fewer] environmental effects" than the other options.

Some 200 scientists and engineers from 18 nations attended the four-day conference here. Among the many topics discussed were the contrasting worth of arctic versus antartic icebergs, the use of satellite imagery to identify and track icebergs, determining which icebergs would be good candidates for towing, the legal aspects of towing such a huge mass through shipping lanes, and the hydraulics of moving an iceberg through the water.

Prince Faisal himself submitted a paper suggesting the feasibility of using side-mounted paddle wheels as a means of propelling an iceberg through the water. Other suggestions included propulsion by osmosis, utilizing the difference in salt content between the fresh water of the iceberg and sea water. Another method suggested using the water. Another method suggested using the difference in temperature between the iceberg and the sea to generate electricity which could then be used to help move the iceberg.

Capt. William Searle, retired from the U.S. Navy, now a consultant in Alexandria, Va., suggested that perhaps the most efficient way of moving the ice would be with two or three large nuclear-powered submarines. Tow of these would be moved under the stern of the iceberg and the third would be under the bow to help steer it.

Each tug would be of 100,000 horsepower. Seatle said such power was easily feasible in a nuclear submarine. He estimated this system could achieve a speed of three knots.

Faisal indicated another conference would be held in about a year and said he hopes it could be held on board an antarctic iceberg.