An army of nearly 2,500 federal, state and local law enforcement officers is poised to begin raids against marijuana growers in all 50 states on Monday, but federal sources said yesterday they fear the operation may have been endangered by news leaks.

The sources said Attorney General Edwin Meese III decided last June that he wanted to undertake such an offensive to prove that he considers domestic marijuana production a major offense and to demonstrate to governments in other marijuana-producing countries that the United States intends to enforce its laws.

Neither the Justice Department nor the Drug Enforcement Administration, which is coordinating the operation, would comment officially on the planned raids.

But Justice and DEA officials, who asked not to be identified, said they believe there have been widespread leaks to the news media and that the operation may have been compromised by a story on the upcoming raids that was distributed nationally by the Associated Press on Wednesday.

Federal sources said there was some thought of changing the timing of the raids, but that was ruled out because of the large number of law enforcement officers involved. Sources said officials have planned many simultaneous raids, with as many as a dozen or more expected in a large marijuana-producing state such as California.

One DEA official, who said he suspected that the leaks came from the Justice Department, said, "Our operations people are pulling their hair out. They're afraid that with all this advance notice people could get hurt. They think the growers may harvest what they can over the weekend and then disappear into the woods."

Meanwhile, sources at the Justice Department said they believe the leaks came from DEA.

The issue of the raids was further confused by a news conference held yesterday by Sen. Paula Hawkins (R-Fla.), who is up for reelection in 1986, calling on federal authorities to begin a nationwide eradication program against marijuana.

Richard Paul, an aide to Hawkins, said that Hawkins had received no official word of the raids. He said the news conference had been timed to coincide with the marijuana harvesting season, Congress' August recess, and an environmental impact statement released July 26 by the DEA dealing with the use of herbicides such as paraquat in the eradication of marijuana plants.

The 200-page impact statement, announced in the Federal Register, would allow DEA Administrator John C. Lawn to choose among a number of eradication alternatives in the future, including the use of herbicides, after a 30-day waiting period.

DEA used paraquat spray in the United States until August 1983, when a federal court ruled that an environmental impact statement had to be filed before further chemical eradication could proceed.

Paraquat use is controversial because it can be harmful or fatal to humans in some circumstances, and many states have opposed any future use. One DEA official said it would cause "a firestorm if we say we're going to spray again."

The administration has pushed Mexico and other countries where marijuana is produced to spray with paraquat.

The DEA environmental statement listed three alternatives for future marijuana eradication programs: manual tools, heavy machinery and herbicides.

Manual methods are accomplished with "hand tools and portable power tools, such as hoes, axes, machetes, weedeaters, and chainsaws to cut down cannabis plants," the statement said.

"Mechanical methods use self-propelled machinery, such as mowers [and] reapers . . . . Herbicidal methods use paraquat, along with 2,4-D or glyphosate to destroy cannabis." The report said that paraquat, because it kills the plants so quickly, was the preferred herbicide.

Federal sources said the raids scheduled for Monday would involve only manual eradication efforts.

The impact statement also told of the dangers that agents face in marijuana field raids: "Growers often 'appropriate' large tracts of federal land to cultivate cannabis and frequently take drastic measures to protect this land, including the use of dynamite, booby traps, fishhooks hung at eye level, attack dogs and guns."

The DEA statement said there were reported sightings of 14,000 marijuana plots in 1983, including about 2,000 on federal land. It said 11,169 plots were eradicated.

Opponents of the administration's marijuana enforcement program predicted yesterday that it is doomed to failure.

Kevin Zeese, national director of the National Organization for the Reform of Marijuana Laws, said the planned raids are "nothing that new, just good propaganda."

"The fact that they're doing this shows that after a 20-year war on marijuana, the problem has grown worse . . . . Marijuana use has tripled. Marijuana is now available in every school in the country. It is the second largest U.S. cash crop -- behind corn. But I'm glad they're trying. This kind of major effort is doomed to failure, and the futility of law enforcement will be more obvious," he said.