MIRAFLORES LOCKS, PANAMA -- Officials of the Panama Canal Commission and international shipping experts are expressing concern that the Panamanian government will not be ready to take over the waterway when U.S. control expires at the end of this decade.

There is no talk of revising or amending the 1979 treaty under which Panama is to take charge of the canal. But canal officials and analysts here said the government's inaction has sent shivers through the international shipping community. The canal handles 5 percent of the world's ocean-going trade.

Although the 51.2-mile waterway is no longer the vital strategic and military asset it once was, it remains an important link for international commerce to both coasts of the United States, Japan, Europe and Latin America.

"They're behind the eight ball," said Raymond P. Laverty, an American who is the canal's deputy administrator. "The maritime industry is not willing to wait until 1998-99 to figure all this out."

The government, he said, "is only now focusing on the fact that it has to be done. This planning process should've started several years ago."

Under the 1979 treaty between the United States and Panama, a U.S. agency now operating the canal will turn it over to Panama at noon, Dec. 31, 1999. All aspects of the canal's operation, including security, toll rates and the waterway's 7,600 employees -- currently U.S. civil servants -- will then become the Panamanian government's responsibility.

Under the terms of the treaty, the administrator of the canal since Jan. 1 has been a Panamanian. After eight months of an acting Panamanian administrator, Gilberto Guardia, a businessman and engineer, was installed as administrator Sept. 20. He was the first non-U.S. citizen to be confirmed by the Senate and sworn in as the head of a U.S. government agency.

At the swearing-in ceremony in Washington, Panamanian Vice President Guillermo Ford said the government was committed to the continued efficient operation of the canal in the 21st century.

But Panamanian and American canal officials, as well as representatives of the shipping firms, say the Panamanian government has yet to appoint a committee, or designate an individual, to study the transition.

Even such fundamental questions as whether the canal is to be run as a Panamanian government agency, as an autonomous entity or as a public-private partnership, have not been addressed, officials say.

The uncertainty about the canal's future is compounded by increased international competition and flat revenue and tonnage figures for the last several years.

After decades of dramatic growth, use of the canal has leveled off, in part because of declining U.S. imports of Japanese cars, sluggish grain sales and slower economic growth in the United States and Japan.

Mounting competition, especially from an oil pipeline crossing Panama and the increased use of trains double-stacked with containers to transport goods across the continental United States, cut into the canal's business in the 1980s.

Toll revenue, which was $329 million last year, has changed little since 1986, and the number of ships plying the waterway has also held steady at around 12,000 annually. Revenue and transits fell off sharply after 1982, with the completion of a trans-Panamanian oil pipeline to handle Alaskan North Slope oil on its way to the eastern United States.

At the same time, world commerce has shifted to huge vessels such as oil supertankers that are too big for the canal. A commission composed of American, Japanese and Panamanian representatives is studying alternatives to the canal -- such as a sea-level alternative, parallel to the current waterway.

Given long-term projections of slow growth in the number of ships using the canal and steadily increasing costs for labor, maintenance and equipment, there is some concern here that Panama may be inheriting a white elephant.

The uncertainty is said to have stirred considerable anxiety in the ranks of the canal's employees, a force that includes many skilled workers. After the government, the canal is the largest employer in Panama.

Although about 87 percent of the employees are Panamanians, all are considered U.S. government employees and are treated as American civil servants, subject to the same benefits and rules as federal workers in the United States.

In Panama, jobs at the canal are highly sought after, and many canal employees praise the civil service system as an island of meritocracy in a country where nepotism, influence-peddling and old-boy networks often determine government hiring decisions.

"I'm afraid that when {the United States} pulls down the flag, a hell of a lot of people will get off the ship," said Edmund A. Blennerhassett, who has worked as a shipping agent in Panama for 30 years.

"Panama has to adapt their procedures and ways of doing things to an American system, or they have to modify the Panama Canal to fit the Panamanian mode," he said. "The problem is, they don't plug into each other. You've got a Panamanian socket and an American plug."

Worries about Panama's ability to run the canal efficiently have been fueled by the country's experience with the canal's two ports, Balboa, on the Gulf of Panama, and Cristobal, on the Caribbean near Panama's second largest city, Colon.

Both ports were developed by the United States as part of the canal operations in the early part of the century, and both were turned over to the government of Panama in 1979 after the canal treaties were signed. Cristobal, on the Atlantic side, handles large volumes of cargo from the huge duty-free zone in Colon. Balboa, on the Pacific side, is mainly a refueling and servicing center for ships using the canal. They represent two of Panama's most valuable industrial resources.

Until U.S. invasion troops ousted Gen. Manuel Antonio Noriega last December, officials neglected the ports "completely -- little new equipment, little investment, corruption all over the place," a shipping agent said. "It was a disaster. In the last two years {under Noriega}, they had a carpetbag approach to everything."

The government of President Guillermo Endara is studying how to rehabilitate the canal's ports but has yet to devise a comprehensive plan, officials said. How the government deals with the ports will be an indication of how serious it is about avoiding similar problems after 1999 in managing the canal itself, shipping analysts said.

Another concern is whether Panama will be able to provide security adequate to ensure the canal's safe operation. In the early 1980s, U.S. policy in Panama was to bolster Noriega's Panama Defense Force, on the assumption that it would ensure the security of the canal after the U.S. shuts down its sizable military bases in Panama in 1999.

Since the U.S. invasion, however, Washington has pushed to demilitarize the force, turning it into a constabulary. Many Panamanians now doubt that the United States is willing to leave the safety of the canal to the currently stripped-down force. Many voice their suspicion that Washington will insist on amending the canal treaties to maintain a U.S. military presence in Panama after 1999.

Most officials publicly dismiss the possibility of a serious military threat to the canal, noting that in any event the treaties afford the United States a role in protecting the canal's neutrality and operations after 1999.

The U.S. Southern Command was vague, however, when asked whether the newly defanged Panamanian military would be up to the job of defending the canal. "There is ample time to address any security concerns that may arise from potential dangers," the command said in a written response to a question.

Questions about toll policy loom over the future of the canal. By U.S. law, the canal is now run as a break-even operation. Since 1979, revenue and expenses have been about equal at $4.1 billion. Although only two toll increases occurred in the 1980s, the canal has managed to raise revenue by special surcharges.

For example, it recently began allowing ships to radio ahead to request priority transit -- jumping ahead of other vessels waiting to ply the canal -- for a substantial fee.