President Reagan's first choice to be ambassador to Panama was an outspoken opponent of the Panama Canal treaties who had denounced the "left-wing and brutally aggressive dictatorship" of the late Panamanian leader Omar Torrijos.

For the Court of St. James's in London, Reagan selected a wealthy businessman and heavy Republican contributor who spent the first 10 days of the Falkland Islands crisis on vacation in Florida.

And for Botswana in southern Africa, the president picked a construction firm executive whose interest in the continent grew out of his enthusiasm for big-game hunting.

Complaints about ambassadorial appointments have been heard for years, but critics argue the Reagan administration's border on an embarrassment. According to new figures compiled by the American Foreign Service Association, the president has installed a higher percentage of political ambassadors, as opposed to career Foreign Service officers, than at any time since the Kennedy administration.

Of 119 chief-of-mission appointments made by Reagan, 41 percent have come from outside the State Department. Of President Carter's 193 appointments, 27 percent were from outside State, the figures show.

Few argue that political envoys are bad per se, and the Reagan administration numbers aren't widely at variance with those of some previous administrations. But critics contend that many of this administration's appointees have had little if any experience or background in foreign affairs. Malcolm Toon, the former U.S. ambassador to Moscow, last spring scolded the president for naming "clunks" to key posts.

"There is a growing concern about the quality of people being sent abroad," said David Newsom, a former career diplomat who served as undersecretary of state for political affairs in the Carter administration and is now director of Georgetown University's Institute for the Study of Diplomacy.

A study by Newsom's institute at the end of 1982 found that out of 100 ambassadors then serving, 31 had "no demonstrated experience in foreign relations." But administration officials, who have become somewhat defensive about their political appointments, more than half of whom come from the business community, say formal diplomatic experience tells little about the "human qualities" that it takes to make an effective ambassador.

"I don't think that simply because someone comes from the Foreign Service, that that makes them a good ambassador," said Helene A. von Damm, assistant to the president for presidential personnel. "Some of the countries prefer to have a non-career ambassador because of the potential proximity and closeness to the political structure, the White House. Sometimes the emphasis is on business development and they like to have a businessman who can help them with the contacts." Von Damm, Reagan's former personal secretary, is Austrian born and is expected to be nominated soon as ambassador to that country.

Aside from the dispute over qualifications, however, critics say the significant increase in political appointees has had a ripple effect on morale at the State Department, where senior Foreign Service officers have found job opportunities cut off at the top.

"All over this town there are senior career people who are unemployed or marking time in make-work jobs," said Elliot L. Richardson, an undersecretary of state (and attorney general) in the Nixon administration and later an ambassador to the Law of the Sea Conference.

Although the arguments are old, the debate over ambassadorial appointments has taken on a new coloration under Reagan. Before 1974, when Congress passed laws limiting individual campaign contributions to $1,000 per candidate, professional diplomats used to focus their criticism on the naming of hefty campaign donors.

"Back in the Nixon administration, there were quite a few guys who chipped in $100,000 on up, given ambassadorial appointments," said Dennis Hays, spokesman for the Foreign Service Association, which represents about 7,000 current and retired diplomats. "We no longer find that. What gets them is their campaign work or they're friends of friends. There are quite a few golfing partners of Walter Annenberg," a longtime friend of Reagan and a member of his informal "Kitchen Cabinet."

A case in point is Theodore C. Maino, head of a construction firm in San Louis Obispo, Calif. A friend of presidential aide Michael K. Deaver, Maino was chosen for Botswana. Maino "fell in love" with Africa during a big-game hunting trip in the 1970s, according to one State Department official.

Then there is Robert Nesen, a Cadillac dealer and Reagan supporter from southern California who was named ambassador to Australia. After Nesen's first news conference in Canberra, one Australian newspaper found him so baffled by basic questions that it concluded that the ambassador "seems to know little or nothing about Australian-American relations or Australian-American differences."

Keith Nyborg, an Idaho potato farmer named envoy to Finland, was chastised by the former Finnish prime minister for "meddling" in an internal political debate over deployment of U.S. missiles in Europe.

Paul Robinson, the ambassador to Canada, is a Chicago insurance executive who faced similar criticism after he commented publicly that the Canadians were spending "too much on social services" and not enough for defense.

Equally troubling to the foreign service establishment are some of Reagan's appointments of ideologically conservative academics. Lewis A. Tambs, a history professor from Arizona State University and canal treaties opponent, originally slated for Panama, was sent instead to Colombia. David Funderburk of Campbell University, an ally of Sen. Jesse Helms (R-N.C.), is ambassador to Romania. Funderburk wrote a 1978 book on the "misteaching of communism" in U.S. universities.

In it, Funderburk warned about the influence of "atheistic" university professors and the "largely liberal leftist news media" whose correspondents "view situations in communist countries via the eyes of Marxist-Leninist terminology."

No ambassador has proved a greater source of embarrassment for the administration, however, than its envoy to the Court of St. James's--John L. Louis, heir to the Johnson's Wax fortune about whom Toon said last year, "His only qualification for the job is that he speaks English."

Louis' decision to finish up his month-long vacation in Florida after the outbreak of the Falklands crisis last year is still a touchy subject at the White House. "Perhaps Louis was ill advised to be away or showed poor judgment," said Von Damm. "But was it a disaster?"