The Long Island Press, perennially the stepchild of New York's glamourous publishing genus, printed its last edition today after 156 years of continual business.

The demise of the Queens-based Press, whose 265,000 daily circulation was more an irritation than threat to the four surviving major newspapers in the New York metropolitan region, was attributed in an angry frontpage editorial to union "featherbedding," declining advertising and poor circulation because of the flight of the middle class suburbs.

But in addition to mounting publication costs, the Long Island Press appeared to be the victim of a relentless circulation attack waged from the west by The New York Times, the New York Post and the Daily News, and from the east from the prosperous abd burgeoning afternoon Long Island daily. Newsday, the nation's furth-largest afternoon newspaper.

As a result, the Press became the first major daily to die in New York City since the ill-fated amalgam in 1967 of the Old New York Herald Tribune, the Journal American and the World Telegram and Sun.

A month ago, Newsday launched a new Sunday Queens edition, putting an expanded reporting team into the populous borough in an attempt to expand its circulation base westward from Nassau County. Newsday officials noted then that Queens is larger in population than all but four cities in the nation. The paper is planning to launch a daily Queens edition next week.

The New York Post, apparently anticipating the long-rumored folding of the Long Island Press, last week began an intensive circulation drive in Queens. News executives at the Post are known to be considering a special queens daily edition.

"There's no question in anybody's mind that they all decided we were very vulnerable. They saw the final outcome, descended on us en masse," said one of the highest news executives on the S.I. Newhouse newspaper chain, which owns the Press.

David Starr, editor of the Press and senior editor of the Newhouse group, said in a telephone interview that the changing character of Queens also contributed to the death of the paper, which long has been the flagship of the Newhouse chain.

"You have to look at the market we were left with. Queens County was always our base, and there's no getting around the fact that the place has changed," Starr said.

He was referring to increasing residential blight and an exodus of white, middle-income families to neighboring Nassau County. Queens has been declining in population.

"A fine newspaper can only do things if it is economically secure. The fact is, the economic base of the Press has steadily eroded over the year," Starr said.

As the middle class fled the city, he said, small businesses and other sources of revenue curtailed their advertising at a time when the paper's production costs were rising.

"Our hopes are now exhausted. There is simply not enough revenue to publish a good local newspaper in Queens without incurring losses forever," he said.

Some Observers of New York's turbulent publishing history wondered when the Press was ever considered to be a "good" local newspaper. Although it recently had invested $10 million in capital improvements, mostly in automated typesetting equipment, the press had long been at odds with its nine unions over the quality of the newspaper.

Its reporters have always been the lowest paid in the New York metropolitan area, and the turnover of professionals has always been the highest. There have been times when the Press has been so short staffed that its editors routinely sent government and private business press releases to the composing room to be typeset verbatim, without further reporting or even checking.

Newsday never considered Press a serious threat in Nassau and Suffolk counties on Long Island, and the Press' circulation on the eastern end of the island recently has been outstripped even by the Daily News. In the competition for advertising linage, the Press was overwhelmed by Newsday.

However, Press officials today placed the blame of the newspaper's death more squarely on the craft unions.