West German authorities announced today that they have proved that seven volumes of the purported diaries of Adolf Hitler are fakes, thus calling into question the authenticity of the entire 62-book set.

Hans Booms, the president of the Federal Archives Office, told a press conference that close scrutiny by historical and crime experts showed that "with regard to content, the alleged Hitler diaries are a grotesque, superficial forgery."

The government statement appeared to put an end to an international controversy begun when Stern magazine announced it had discovered the diaries and confirmed their authenticity, and it began publishing excerpts. Although numerous scholars immediately expressed doubts that the documents were real, other experts consulted by the magazine certified that samples of the purported diaries shown to them were written by Hitler.

Following today's announcement by the archives office, Stern Publisher Henri Nannen said, "We have reason to be ashamed that something like this could happen to us." He added that Stern would cease publication of diary excerpts that began appearing in last week's edition.

Nannen said that the magazine now would try to determine who produced the forged diaries. "We will fully clear up this matter," he said. "We have no reason to protect the swindler."

The Sunday Times of London, whose publisher, Rupert Murdoch, purchased rights to parts of the diaries for $400,000, also declared that it would stop printing excerpts from the bogus volumes but would proceed with its own investigation into the authenticity of the material, including two volumes brought to London this week. Details on Page A16. Paris Match magazine also announced it was suspending further publication.

Booms said that some entries containing factual errors were copied from postwar publications and that linguistic expressions unknown in Hitler's time were included in diary passages.

Louis Werner, of the Federal Criminal Office, said that tests on paper and glue from three volumes discovered materials that were manufactured only after 1955.

The sample volumes were turned over to federal experts for examination this week by Stern to quell controversy over the validity of the diaries.

A Stern reporter, Gerd Heidemann, acquired the 62 volumes from an anonymous source for an undisclosed sum of cash after what he claims was a three-year odyssey that took him through East Germany, Austria, Switzerland and South America.

Heidemann has refused to reveal how he acquired the diaries, even on a confidential basis to his editors, because he claims that the lives of East German sources would be jeopardized.

British historian Hugh Trevor-Roper, who became convinced the diaries were genuine after a brief inspection but later retracted his judgment, expressed regret that he did not exercise more caution in his initial opinion. He added that "for some time now" he has been persuaded that the volumes were forgeries.

Prof. Friedrich Kahlenburg, a senior archives official, said that since Stern admitted that the handwriting in all volumes was similar, he assumed that the complete set of diaries was a hoax.

Booms said that "a lack of authenticity is shown by a row of grave errors, use of expressions found only in the postwar era and incorporation of incorrect facts from published materials."

He said that diary passages allegedly written in 1934, 1935 and 1937 were copied from a book entitled "Hitler: Speeches and Proclamations 1932-1945" published by historian Max Domarus in 1962.

The archives office reached this conclusion by spotting the exact replication of Domarus' errors in the diary entries.

Booms said the forgers were "not very clever since they did not bother to stick in words or change phrasing" in their mimicry of Domarus' work.

While declining to speculate on the identity of the perpetrators, Booms said the source material and the language style employed seemed to point "toward right-wing circles."

He also claimed that since evidence of publications from the early 1960s was uncovered in the volumes, the forgeries were definitely concocted "after 1964, by not very intellectual people."

Booms said the relatively crude manner of reproduction gave the impression that "even a historian from some provincial newspaper" could have acquired similar information and written the entries.

The bogus nature of the diaries also was betrayed by laboratory tests that showed, according to officials of the Federal Crime Division and the Berlin Institute for Materials Testing, that the paper and glue used in some volumes "could not have existed in the respective years."

Tests quickly showed that the diaries marked 1934 and 1939 contained elements produced well after the end of World War II, a revelation that a crime office spokesman said led to the firm conclusion that "the whole set must not be genuine."

In the past week other skeptics have noted that it seemed inconceivable that the Nazi dictator would bother to keep his daily jottings in volumes bound in imitation black leather.

Moreover, the initials in gothic script on the jackets of some volumes reads "FH" and not "AH"--another indication of the forgers' crude handicraft.

Still, the slanting penmanship in the diaries effectively resembled Hitler's writing style and fooled Trevor-Roper as well as a number of other historians and Hitler experts.

Britain's David Irving, a right-wing historian who initially scorned the diaries as fakes by pointing out that Hitler's palsy affliction made writing virtually impossible, later reversed his position and conceded that the diary inscriptions reflected the debilitating effects of the illness.