Pressure from governments to place unqualified people in top jobs at the United Nations is causing the "political corruption" of the international Secretariat, a former American diplomat has charged.

The evolution of a "Kafkaesque bureaucracy ridden with self-interest" has left the staff deeply demoralized, said Seymour Maxwell Finger, who held the rank of ambassador at the U.N. under Adlai Stevenson and Arthur Goldberg in the 1960s.

Finger now heads the Ralph Bunche Institute at the City University of New York Graduate Center here.

Finger's 17-page monograph on the Secretariat was based on interviews with 50 U.N. staffers. The study, circulated quietly among high U.N. officials, including Secretary General Kurk Waldheim, has produced consternation, but as yet no decisive changes in attitude, according to one reform-minded U.N. official.

In it, Finger charges that the political pressures form governments are matched by the tendency of high U.N. officials to hire "friends, relatives and those who support their special interests, rather than promote competent people."

Even the United States, Finger said in an interview, has joined the majority of nations in "zeroing in on particular, influential jobs for favorite candidates."

His report is a follow-up to a similar study done five years ago. In that time, he says, "the situation has not improved."

Since the Third World gained control over the General Assembly a decade ago, the West has sought to retain its power over vital U.N. functions through the veto in the Security Council and the retention of key Secretariat jobs by candidates of Western governments. The Third World nations have come to believe that their Assembly resolutions are being thwarted by the perceived pro-Western bias in the Secretariat. This fall they will attempt to change the formula determining each country's job quota, one now heavily weighted in favor of the largest contributions to the U.N. budget.

This competition for jobs, Finger notes, has eroded the original ideal of the impartial international civil servant, and the willingness of all nations to trust the Secretariat's objectivity.

The result is a "climate of apathetic conformity" that has caused many of those interviewed by Finger to hold out little hope of progressing in the organization because "the criteria of merit are subordinate to political clout."

There are, however, "good signs" of potential reform, he continues.

Waldheim is aware of the problem and one year ago appointed a new personnel chief, James Jonah, with a "reputation for courage, integrity and high standards." But 70 percent of those interviewed, Finger says, feel the reforms have been too slow.

Jonah, a national of Sierra Leone, was recruited by the late Ralph Bunche and served under him in the U.N.'s elite peace-keeping division. In the eyes of many staff members, he is Bunche's heir apparent as a symbol of the international civil servant working for the institution rather than any outside interest.

Jonah, responding to Finger's charges, said in an interview that "many governments are prepared to try a system free of pressure if they have a reasonable assurance that no one is going to succeed in exerting pressure."

But Jonah's new system is being challenged from within other U.N. officials said, by ranking department heads who continue to try to trade jobs under their control for political favors.

Jonah says he is adamant on the principle of not bowing to outside pressures.