The nation's 6,400 major hospitals have decided to add financial clout to their already effective lobbying operation by forming a political action committee to funnel campaign contributions to friendly members of Congress.

The American Hospital Association's new move will put the typical community hospital - nonprofit in aim, often charitably and religiously oriented - into the same kind of big-dollar politics as business and labor.

The decision to form a political action committee comes in a year when American hospitals have successfully blocked an administration effort to put a lid on rising hospital costs.

A key hospital aim is to keep resisting what hospital officials expect to be a continuing federal battle to limit their prices and multi-billion-dollar revenues.

Hospital association officials plan similar efforts against what they consider the "wrong" kind of national health insurance against any stricter regulation of hospitals under any health insurance plans and against federal efforts to put together controls on hospital building, expansion and equipment.

The AHA goal is to raise $100,000 a year initially and gradually work up to "several hundred thousand dollars" yearly, AHA President John Alexander McMahon said.

The sum might then approach the war chest of the giant of medical political action groups, the American Medical Association's AMPAC - American Medical Political Action Committee. So far this year it has raised $1,036,000, of which $925,000 already has been given to congressional candidates.

The AHA money, like the AMA's, would go to incumbents or challengers "on a bipartisan basis" in $1,000 to $10,000 chunks, starting in 1980, McMahon said. The $10,000 gifts would only become possible "when we can afford that kind of maximum," he said. Election law forbids contributions larger than $5,000 in an election, but the primary and general elections are considered separate.

In alliance with the AMA and the Federation of American Hospitals - the smaller association of hospitals owned by investors - the AHA in recent months has mounted an intense campaign against a tight national limit on hospital revenues.

The AHA twice summoned hospital officials from across the country to visit their congressmen to urge suport of voluntary cost controls by the hospitals.

In a Mailgram this week, the AHA again urged all hospital administrators, trustees and doctors to contact their senators immediately to "demonstrate all out opposition" to a last-ditch attempt to force a Senate vote on hospital cost control.

Actually, that Senate effort - sponsored by Sen. Gaylord Nelson (D-Wis.) and Sen. Edward M. Kennedy (D-Mass.) - would merely enact stand-by controls if the hospitals own efforts fail, and the measure is given only a thin chance.

Nonetheless, McMahon said, "We still have a lot of legislative education to do. We have had too many 21-20 votes" on cost control in the House Commerce Committee.

Twelve state hospital associations already have their own state political action groups to support candidates for state legislatures and other offices. Twelve more reportedly are getting ready to start their own "PACs."

"I've been urging for five years that the AHA get into a political hardlobbying posture," said Ray Hurst, president of the Texas Hospital Association, long a politically oriented group. "I think what we're seeing is a delayed realisation by hospital people who always considered themselves a little above politics.

"Now they see that we've yet to get involved in the political areas because the politicians are after us. They want to control us. Texans still believe in free enterprise, motherhood and the flag and "leave us alone."

The decision to create the new PAC was announced to AHA members at the group's mid-year meeting in Ameheim, Calif, this month. Nonprofit hospitals make up most of the AHA's membership. Of the 7,000 U.S. hospitals, the AHA represents 6,400 in effect all but some of the smallest.

Slightly more than 1,000 hospitals, which are neither non profit nor governmental, are investor-owned and profit-seeking.