Despite widespread support in and out of Congress, legislation assuring victims of price-fixing conspiracies of their right to sue for damages faces a probable death this session of Congress.

Without congressional action, courts already have begun dismissing pending suits that could add up to $1 billion to state, federal and local coffers.

Nevertheless, because of vehement opposition to the bill by Sen. Orrin G. Hatch (R-Utah), it is becoming increasingly unlikely that the measure - approved by both judiciary committees - will be scheduled for floor consideration before congressional adjournment, experted in mid-October.

The Senate leadership has been unwilling to schedule floor debate during the final weeks of the session for any measure that promises to be controversial unless senators can agree on time limits for the debate. Sen. Hatch, who already has dumped into the hopper more than 100 proposed amendments to the three-page bill, says he will not agree to a time limit.

"I just don't think that in these waning days that you do that," he said yesterday. He added that he would "probably have 100 more amendments ready" by the time the bill would come up if the leadership decides to schedule it. (The House leadership has promised to take the bill to the floor if there is a promise of Senate action but doesn't want to waste its time.

The measure is intended to overturn a decision by the Supreme Court last year, now referred to as the Illinois Brick decision, which held that only the direct purchasers of a product may sue under the antitrust laws to collect the allowable treble damages.

The bill would allow businesses, consumers and governments injured by antitrust violations to sue to recover damages whether or not they have dealt directly with the antitrust violator. Very often, the injured parties of price-fixing conspiracies are the indirect purchasers. For instance, government units often purchase products through distributors and contractors, small businesses purchase products through wholesalers and consumers purchase products through retail stores - not directly from a manufacturer who might have been part of a price-fix conspiracy.

Supporters of the legislation say that because of the court decision, consumers who paid prices inflated by price-fixing schemes have no recourse to collect damages from the antitrust violator because they bought from a middleman.

President Carter, who supports the bill, complained in a letter urging enactment that without the bill, "Anticompetitive behavior may go unpunished in those instances where direct purchasers have passed on overcharges or otherwise have little motivation to bring an action."

Besides the support of the administration and a plethora of consumer and union groups, the governors and state attorneys general of all 50 states have been urging passage.

The federal, state and local govenments as a group stand to lose between $500 million and $1 billion in damages in pending suits subject to dismissal without some congressional action.

Already courts have begun dismissing some of the pending damage suits. At the end of last month, for instance, a federal court dismissed a suif filed by the State of Texas seeking $10 million trebled for damages suffered as a result of buying reinforced steel bars at prices inflated by an alleged conspiracy.

Although lawyers for the state said they have evidence showing the state was overcharged by $10 million - which would have added $30 million to the state coffers - the suit was dismissed before the evidence could be presented because the state had purchased the steel bars from a contractor, not the manufacturer.

"The public has been clamoring for tax relief and yet a bill that would allow federal, state and local governmental units to recover hundreds of millions of dollars from price fixers has been stopped in its tracks . . ." Sen. Edward M. Kennedy (D-Mass.), chairman of the Senate Antitrust and Monopoly Subcommittee, complained yesterday.

Kennedy has lined up support for the measure from more than 60 senators from both sides of the aisle despite the heavy lobbying against it by the Business Roundtable. Chamber of Commerce, National Association of Manufacturers, Food Marketing Institute and members of industries that read like a Who's Who of former price-fixing violators.

"The Illinois Brick opinion has virtually immunized large manufacturers from the antitrust laws and they will not lightly give up this new-found immunity," Kennedy charged yesterday. He said that "a few large manufacturers have managed to convince one or two senators to take up their cause."

If the measure fails to get through this year, he vowed it would be his "top priority" for early next year when he takes over leadership of the Judiciary Committee.