Poland's Army newspaper tried to tell an American joke today but it backfired.

Zolnierz Wolnosci, a newspaper known best for its reflection of the thudding hard-line opinion of the ruling military council, prominently displayed a bold-face article and 16-point declaration purportedly based on a "top secret NATO document."

The NATO states, it said, meeting in Brussels earlier this month, had called on the leaders of the United States, Britain, Italy, France and West Germany to restore civil liberties in their countries.

Unless action was taken promptly, the "document" said, the Western allies would consider disbanding NATO "as an organization discredited by the above-mentioned states."

The allies were said to have condemned what they called "the further expansion of American military bases outside U.S. boundaries and participation by the United States in the quelling of national liberation movements in Latin America" and denounced the use of force by Britain against freedom-loving Irish patriots.

An anonymous Communist agent had passed the document to its star reporter, Col. W. Zielinski, the paper said.

After Western news agencies in Warsaw had filed stories taking the Polish paper's report at face value and even PAP, the official Polish news agency, had distributed a straight-faced account of the article, some readers had second thoughts.

Could the colonel's apparent scoop be an example of Polish military humor?

Contacted by The Washington Post, a spokesman for Zolnierz Wolnosci said the article was in fact a "commentary," prompted by the imposition by NATO of trade sanctions against Poland and the Soviet Union following imposition here of martial law. He refused to identify himself or give further details.

But shortly after, PAP issued a note to editors instructing them to disregard the Zolnierz Wolnosci report.

"This is not a serious article," the note explained, advising that Col. W. Zielinski's effort "should be read as a column of the Art Buchwald or Russell Baker type."