Labor and Democratic Party leaders formally ended their trial separation yesterday and vowed to live and work together, at least until the Republicans have been forced out of the White House and the Senate majority.

The reunification came at the initial meeting of the Democratic National Committee's new 20-member Labor Council, which has as its first goal the election of a pro-labor Congress in 1982.

The council's creation "marks the reaffirmation of the . . . partnership between working men and women, organized labor and the national Democratic Party," DNC Chairman Charles T. Manatt said yesterday after a three-hour council meeting.

He said the council is the party's tangible "recognition that, in the last 10 years, organized labor has not taken a direct, active role in the party's activities."

But Manatt implied that the basic material used in putting together the council--a tenuous amalgam of liberal and conservative union presidents--was hostility toward the Reagan administration's domestic policies. In its first year in office, the administration has shown itself to be "the most anti-union, anti-worker administration in this country in the last 50 years," Manatt said.

Robert Bonitati, White House chief of labor liaison, objected to that description yesterday.

"I think it would be far healthier if the labor representatives would take a more bipartisan approach. Instead of putting all their eggs in one basket, they should be making a conscientious effort to participate in the Republican Party at national, state and local levels," Bonitati said.

Council co-chairman Glenn E. Watts, president of the 508,000-member Communications Workers of America, said much of organized labor has decided to return to the Democrats because of mistreatment from Republicans such as Sen. Orrin G. Hatch (R-Utah), chairman of the Senate Committee on Labor and Human Resources, who has opposed organized labor's legislative programs frequently.

Watts said Hatch would be a prime target for removal by organized labor in 1983, when the senator's current term expires. Watts said labor "will spend all of the money we can get our hands on" to get Hatch out of office.

Watts, who also holds a regular seat on the DNC, said his service on the Labor Council means that, as an organization, the CWA has "an association" with the Democratic Party. But he said that does not mean that CWA members who are Republicans or want to support Republicans will be forced to support union leadership in political matters.

John T. Joyce, president of the International Union of Bricklayers and Allied Craftsmen, also a council co-chairman, said the unions' affiliation with the Democrats "essentially is an organizational relationship that really begins with issues." That does not mean the unions "will stand to one side" if those issues are not addressed, he said.