Labor and consumer leaders will file a suit in U.S. District Court here today alleging that the Reagan administration's refusal to rehire fired air traffic controllers is disrupting air travel and endangering public health and safety.

The suit was announced here yesterday at a news conference called by Douglas A. Fraser, president of the United Auto Workers union, consumer advocate Ralph Nader and five other plaintiffs in the case.

Fraser said the strike by the Professional Air Traffic Controllers Organization that began Aug. 3 "for all practical purposes, has been lost.

"The union's been destroyed. . . He President Reagan has not only won the battle. He's won the whole goddamned war," Fraser said. He said the administration "has gotten its pound of flesh and now should exhibit an ounce of compassion" and rehire the controllers.

Transportation Secretary Drew Lewis and Federal Aviation Administrator J. Lynn Helms are named as defendants in the suit. Lewis and Helms, on orders from Reagan, fired 12,000 controllers who had ignored a presidential back-to-work deadline of Aug. 5. FAA officials said yesterday that 11,438 of those controllers have received final dismissal notices and will not be rehired.

The suit says the plaintiffs and other air travelers are being denied safe and efficient service "because the defendants--solely because of a strike, which for all intents and purposes is over and done--refuse to hire from an available pool of trained, experienced and qualified air traffic controllers and instead rely on an inexperienced and overworked air traffic control work force . . . "

Linda Gosden, Lewis' press secretary, said the suit is groundless. Domestic air traffic is safe and operating at about 80 percent of normal capacity, she said.

In a related development, FAA officials said they are using a new test designed to improve the selection of candidates for air traffic controller jobs.

The test "weeds out" at least 10 percent more of the weaker applicants for training at the FAA Training Academy in Oklahoma City, Okla., a function that should lower the failure rate of clases admitted to the school, academy spokesman Mark Weaver said.

Concern about the academy's testing and training methods was voiced last week when the government announced that half of the first class of 72 students studying to replace fired controllers flunked. Another 12 students quit for personal or other reasons.

Weaver conceded that the percentage of students who flunked was "higher than normal, by quite a bit." But he said two prestrike classes, the last one in 1977, had similar rates of failure. "The average washout rate is about 25 percent," Weaver said.

James O. Boone, FAA chief of systems analysis and research, said the first poststrike class was "an unusual group," largely chosen from a prestrike list of about 9,000 persons who had qualified for controller training. They had taken the old test, but many had "passed"--a minimum grade of 70 is required--because of "point allowances" for military service, education and any prior controller experience, Boone said.

Only about 8 percent of students in the first poststrike class had significant controller training compared with about half of those in previous classes, Boone said. Also, the test taken by the first class primarily was designed to measure general reasoning skills such as mathematical ability and spatial judgment. Those factors meant the first class "did not have a high predictor of success," Boone said.

He said the new test "more directly measures abilities" needed to conduct air traffic. For example, applicants now are asked to read a graphic display of a radar screen, to judge time and distance of "moving" objects on the screen and to determine when those objects will meet and how much distance and time is needed to keep them from meeting. The aim is to determine "three-dimensional reasoning" needed by a controller, Boone said.

Because of the normally high attrition rate in controller training, at least 200,000 persons will have to take the test for the FAA to come up with the 7,000 or so new controllers it says it needs to operate the air traffic control system at full capacity by 1983, Boone said.

About 125,000 persons applied for the fired controllers' jobs, which pay an average annual salary of $33,000. FAA officials said about 45,000 of the applicants have taken the new exam, and that about 26,000 passed. Testing began Oct. 15 and will end Nov. 30.

About 25,000 persons usually take the test for controller jobs every year, and 10,000 of them usually make it to the waiting list. Of those, about 2,000 are selected for the academy, where about 1,500 of those admitted pass the 17- to 20-week course. About 1,250 of the academy graduates succeed in required on-the-job training and become controllers, Boone said.