A high-ranking Secretariat official has been fired on charges of embezzling about $200,000 within the past year from a million-dollar U.N. trust fund for Namibian refugees, according to a U.N. document obtained today.

Augustus Fahnwulu Caine, a former Liberian diplomat who had worked for the United Nations for a decade and risen to the top rank in its civil service earning $75,000 a year, was dismissed May 28, the records show.

One staff member who has been with the United Nations for about 30 years said, "There have been cases of embezzlement here in the past--no bureaucracy can escape that--but this could well be the biggest ever."

U.N. officials said the 50-year-old Caine had denied the charges and filed a notice of appeal. Several phone calls to Caine's White Plains, N.Y., home went unanswered this afternoon and tonight.

The U.N. document alleges that he "knowingly falsified signatures" on checks that should have gone to pay for the education and training of refugees from Namibia, a territory also known as South-West Africa and ruled by South Africa.

The United Nations allocates $1 million a year to this trust fund, but a special investigative tribunal concluded that about $200,000 of that amount, made out to apparently false names, ended up in Caine's pocket instead.

Caine's title was Director of the Office of the U.N. Commissioner for Namibia, and in that post he had the authority to sign the checks mailed to individuals enrolled in the refugee education programs, U.N. officials explained.

They said that Caine had claimed he was the victim of "sloppy accounting practices."

The special tribunal ruled that if Caine were willing to return the money, the United Nations "will refrain from further legal action. However, if he is unwilling or unable to return the funds, the United Nations will take whatever action it deems necessary to protect its interests."

The firing was not revealed publicly. U.N. officials explained the omission by saying that the case is under appeal and that hope remains that Caine will turn over the $200,000 they say he took.