In what Western observers saw as a highly unusual occurrence, a Leningrad literary magazine has published a fictional article interpreted by some Soviet readers to be a scathing satire on President Leonid Brezhnev's public activities and his continuance in office despite his advanced age.

The journal Avrora carried the piece in its December issue, which was dedicated on the inside cover to Brezhnev's 75th brithday and carried his photograph. Avrora circulates mainly in Leningrad and issues have reached Western correspondents here only recently.

What made the 300-word fictional piece, entitled "Jubilee Speech," curious was the fact that at the time of its appearance, the Soviet leader had been hailed in the press as one of "the planet's best read authors" for his numerous books about achievements of communism and his own career.

The piece in Avrora focuses on a great and prolific author long thought to be dead. "It's hard to believe that this wonderful writer is still alive," it said. "One can hardly believe that he walks the same streets as the rest of us. He should be dead, he wrote so many books. Any human being having written so many books would have been in the grave a long time ago.

"But this one--this one is truly inhuman. He lives on and does not even think of dying, to general consternation. The majority thinks of him as having been dead for ages, such is their admiration for his talent.

"His place is there beside" Dostoevsky, Balzac and Tolstoy, the piece continues. "He deserves the honor. Here he sits, right in front of me, red-cheeked and chubby, and its hard to believe that he will die. And even he probably does not believe that he will die. But he will, sure as taxes.

"A monument will be erected to him and a race course will be named after him; he was so fond of horses. His grave will be ringed with a picket fence so he can relax. We will see his graven image on the picket fence."

Some observers here pointed out that, seemingly in keeping with Brezhnev's age, the piece was printed alone on page 75. Others contended that the journal had since been withdrawn from libraries.

There are no indications here of any political rivalries to suggest threats to Brezhnev's leadership despite his frail health. But embarrassing rumors have been circulating here about various members of Brezhnev's family and the Avrora piece was seen by some as a joke by Leningrad literati on extravagant official praises bestowed on the leader's rather wooden literary accomplishments.

The author of the piece, Viktor Golyavkin, voiced the hope that "we won't have to wait for long" to hear praises heaped upon the great writer at his death. "He won't disappoint us. We all so believe in him. Let's hope that he completes the work still in hand and gladdens our hearts as soon as possible."

The wife of the author, contacted at their Leningrad home by a journalist, said the piece had been written long ago and was submitted to the journal several months before being used. It was not her husband's fault, she said, that the "story appeared in a particular issue."