In a major departure from the hands-off policy of George Meany's final years, organized labor is becoming a financial mainstay of the Democratic National Committee. Using a combination of "hard" and "soft" money, labor unions are expected to provide the DNC with at least $1 million, just under 20 percent of its annual budget.

Michael Steed, DNC counsel, said he and Charles T. Manatt Jr., the party chairman, have been asking union presidents "for $15,000 in hard contributions and $100,000 in soft contributions."

Hard contributions are those from funds that union political action committees collect and turn over to candidates for federal office, under limits set by federal law. Soft contributions refers to money that does not go to federal candidates and which is not subject to federal regulation.

With the United Auto Workers and the Communication Workers of America leading the way, the drive has produced $445,000 in contributions and commitments, and interviews with union officials suggest that the $1 million goal will be achieved with relative ease.

"Where your heart is, is where your treasury is going to end up," said one political director of a union that is almost sure to give a significant amount of money to the DNC. Another official, John Brown of the Operating Engineers, said his executive board has not formalized a decision but "we don't expect any problems. We're going to come in with both feet."

For the Democratic Party, which has been having severe difficulties maintaining a semblance of a financial base, the union money is both a lifesaver and a means of picking up substantial contributions without the constraints of the donation limits set by federal election law.

In seeking the "soft" contributions of up to $100,000 from unions, the DNC is taking advantage of provisions that permit unlimited giving as long as the money does not go to federal candidates.

"Soft" money must be used instead for such activities as voter registration and education programs, or to finance the cost of state and local elections. Republican sources said the GOP does the same thing, although most of its soft money is corporate, not union. Republicans describe the money, which is legal, as "dirty" money.

The financial backing is a key element in what amounts to a nearly complete turnabout in the relations between organized labor and the Democratic Party structure during the past year.

Labor has always mainly supported Democrats, and most unions supported Jimmy Carter against Ronald Reagan last year. What is unusual now is the degree of support for the party structure, and in an off-year at that.

The two split bitterly after the nomination of George McGovern for the presidency in 1972, when Meany, then AFL-CIO president, effectively withdrew from active participation in the party on the grounds that it had been taken over by leaders of the Vietnam, civil rights and other protest movements.

With the death of Meany in 1980, the subsequent elevation of Lane Kirkland to the AFL-CIO presidency and the election of so many conservative Republicans last year, leaders of organized labor have rejoined the party in force.

In February, 15 of the 25 at-large Democratic National Committee seats were assigned to representatives of organized labor. In the same month, the AFL-CIO executive council ended a prohibition on participation in primaries, a policy shift that technically opens wider involvement in both parties, but in fact was directed toward gaining stronger leverage in the candidate selection process within the Democratic Party.

The day after the inauguration of President Reagan, Kirkland said, "We do not want to be captured by the Democratic Party, but we want to increase our influence in the party. . . . I sense a growing feeling within the party that it's time to get back within the mainstream. I think I know what the mainstream is."

Steed said "when George Meany wasn't really sure where the Democratic Party was going, to a certain extent he turned organized labor, not away from the party, but he just didn't do a lot with the party. Now we see a very significant increase in activity."

While party officials and most union leaders are delighted with the new relationship, one participant with ties to both camps warns there is a danger, not that labor might be captured by the party but the opposite.

"The only group the party is having real success with in the effort to improve fund-raising is organized labor. The danger is that organized labor is going to end up owning the party," this political strategist, who asked not to be identified, said.

Ann F. Lewis, political director for the DNC, contended, however, that the election of Reagan and the GOP takeover of the Senate has significantly altered the fund-raising climate for the Democratic Party.

"What we had until this year was a certain amount of 'access' money. It was mostly business money and it was split evenhandedly between Democrats and Republicans. What has happened since the Reagan administration is that giving money to the Democrats is seen as no longer essential," Lewis said.

She said Democratic Party leaders have gone to unions with the argument that "Look, we are not going to get it from big oil, and we need to get the support from our friends."

Lewis argued that the seeking of contributions of up to $100,000 from labor unions, soft money, is justified because "there are a finite number of labor unions and there are very strict limits on the amount they can give to federal candidates , so if you want to increase the size of the universe, the only way you can do it . . . is to look at the non-federal area."

A union official supported the growing financial commitment on the grounds that the GOP has developed fund-raising to a fine art, and the DNC effort is like "setting up an ABM system to counter Russian deployment of an MX system."

As of June 30, the DNC reported that it had raised just $1.76 million, less than 10 percent of the $19.83 million raised by the Republican National Committee during the first six months of the year.

Steed said the two largest contributors to date are the UAW and the Communication Workers, each of which has given $50,000 in "soft" money. The UAW is committed to give another $50,000, he said.

In addition, he said at least seven other labor organizations have given the maximum amount of money, $15,000, from their PACs. They are the National Education Association, the American Federation of Teachers, the International Brotherhood of Operating Engineers, the Brotherhood of Railway, Airline and Steamship Clerks, the United Mine Workers, the Seafarers' International Union, and the United Steelworkers of America.

Of the contributions and commitments received and made to date, Steed said $254,000 is in "soft" money and $191,000 in publicly reported money from PACs.

Steed said that while unions have by no means unanimously joined the fund-raising effort, none has said it will refuse to participate. He said, however, that in the case of the Teamsters union, which backed the Reagan campaign, "I believe we have sent letters and have received no response."