AFL-CIO President George Meany charged yesterday that organized labor is the target of a multimillion-dollar extremist campaign that can be compared to the rise of Nazism in pre-World War II Germany.

In a strongly worded Labor Day address on CBS radio, the 83-year-old labor chief said extremism is on the rise in America and "its No. 1 target is the American labor movement."

Meany's assault on what he called the "hate merchants of the '70s" comes at what could be a crucial juncture for organized labor, whose foothold in the American work force is slipping even as it is pushing in Congress - with indifferent results so far - for its most ambitious legislative agenda in years.

Last week the Labor Department reported that American membership in labor unions dropped by nearly 4 per cent during the last two years, the first decline since the early 1960s.

Moreover, a strong and well-coordinated business lobby has emerged on Capitol Hill to threaten its legislative program, including the administration-backed plan for overhaul of the nation's labor laws to make it easier for unions to organize and win contracts.

Meany said "extremists are at it again" in the fight over labor law revisions and accused them of trying "to once again manipulate public opinion in order to split apart workers, minorities, family farmers and others who have often worked together to move this nation forward."

Said Meany: "It is not little old ladies in tennis shoes who are the hate merchants of the '70s. It is slick Madison Avenue types, trained in mass psychology and propaganda techniques, who have a computerized mailing list, a printing press and a government-subsidizing mailing permit."

Without identifying the source, he said "an estimated 150 million letters will be mailed, seeking contributions to fight a host of so-called enemies to the American way of life." He said estimates of the cost range from $25 million to $50 million.

Drawing a connection between "extremist rhetoric" and "violent acts," he cited what he called a "disturbing number of reports of increased [Ku Klux] Klan activity, 'maneuvers by well-armed and heavily financed para-military right-wing groups and others." He said "posses" have shot at union workers in California, Idaho and Maryland, and Klansmen burned crosses and vandalized presses of a union newspaper in Kentucky.

"While those more respectable business leaders who are backing the extremist attacks on the labor movement disclaim violence, their words and deeds are spawning that violence,' said Meany. "When corporations openly violate and flout the labor law, they set an immoral example for lawbreaking that all too often is translated to pressure on a trigger."

Meany singled out several corporate figures for criticism. He accused Joseph Coors, the conservative brewery executive, of demanding the right to force his workers to submit to lie detector tests and company searches, and said firms such as J.P. Stevens, Winn-Dixie and Deering-Milliken are violating labor laws while professing to support free choice for workers on joining or not joining unions.

In drawing a parallel with Nazism, Meany said:

"Conservatives and some business leaders who kid themselves into believing they can use the extreme right wing to weaken and eventually destroy organized labor are playing a dangerous game.They would do well to remember - as we in labor remember all too well - what happened to the German industrialists who financed Hitler's Nazi movement because it was pledged to destroy the unions.

"After turning free unions into a huge, national compulsory company union - called a Labor Front - Hitler pounced on his industrial supporters, incorporated their plants into his totalitarian system, and reduced the former managers to mere office boys."