The United Auto Workers has abandoned its official hands-off policy toward the race for the Democratic presidential nomination, triggering a UAW push for Sen. Edward M. Kennedy (D-Mass.) in several states, including such bellwethers as Florida and Iowa.

Although the 1.5-million-member union was a big factor in President Carter's successful 1976 campaign, UAW President Douglas A. Fraser now predicts that Kennedy is the "overwhelming favorite" among rank-and-file auto workers.

"In a head-to-head run against Carter, Kennedy would be the overwhelming favorite among our active people," Fraser said in an interview with the Dallas Times Herald.

Fraser said the UAW International Executive Board's vote Monday to let union officers support the candidate of their choice came largely at the urging of UAW members in Florida and other states with early selection processes and growing draft-Kennedy movements. Such a move is unusual for the UAW this early in the political calendar.

In Iowa, where the UAW helped launch Carter in late 1975, among those deserting him was Chuck Gifford, the union's top political operatives in the state. Gifford had previously said he would support the president as long as Kennedy remained a noncandidate.

The shift in loyalties is significant because in addition to his UAW post, Gifford is a member of the Democratic National Committee and was an early 1976 Carter backer.

It underscores the strong labor backing already behind a draft-Kennedy movement in Iowa.

Most of the state's top union leaders have endorsed Kennedy and many are actively engaged in organizational work aimed at electing Kennedy delegates and dealing Carter a severe political blow in the Iowa caucuses, the first in the nation.

"At this point I expect to go to the caucuses as a Kennedy delegate," Gifford said in an interview with United Press International. "Given the same set of circumstances we have now, Carter isn't going to make it in the caucuses."

Regional director Robert Johnson said he issued the directive after the union's International Executive Board concluded the country "is drifting" under President Carter and needs new leadership.

A UAW official in Des Moines predicted a majority of the union's 18 regional directors will follow Johnson's lead. "I think you're going to find some quick lining up behind Kennedy," the official said. "Some of these people have just been waiting for the word and to them this is as good as a full-scale endorsement."