A massive coalition of labor and welfare groups is forming to battle President Carter over his expected proposals to cut Social Security benefits.

The coalition, which includes former secretary of health, education and welfare Wilbur J. Cohen, AFLCIO Secretary-Treasurer Lane Kirkland, United Auto Workers President Douglas Fraser and former Social Security commissioner Robert Ball, wants to head off an anticipated $600 million in cuts expected to be asked by Carter in his new budget.

Its members say they fear that these proposals are only the first step in a longer-range effort by the administration to slash Social Security benefits even more.

Although the Carter proposals haven't been made public, they have already caused considerable behind-the-scenes battling. Ball and Cohen met with Carter and HEW Secretary Joseph A. Califano Jr. last month to protest strongly.

Earlier this week, the president's counselor on the aging, Nelson Cruikshank, who is also chairman of the Federal Council on the Aging, was reported by friends to be ready to resign in anger over the Social Security cuts. He deferred a decision after a private meeting with the president.

The first public protest over the cuts is to come today from 20 organizations of the aging.

On Jan. 25, Cohen, who helped write the Social Security Act in 1935 as a youthful social welfare expert, will convene a meeting of major national groups to set up a new organization called Save Our Security.

Its aim is to get Congress to kill the Social Security cuts to be proposed by Carter.

Other members of the group include Eleanor C. Smeal of the National Organization for Women, Aaron Henry's National Black Caucus on Aging, William Hutton of the National Council of Senior Citizens, the Coalition of Citizens with Disabilities, and many other groups and individuals who are expected sign on within the next few days.

Hutton said yesterday that while the initial cuts would total $600 million in fiscal 1980, their impact would deepen tenfold in the next five years. Carter has hinted at still other revisions -- and a rollback of scheduled payroll tax increases -- in the future.

Cohen, Ball and others, who are having their first serious public fight with the administration, say they believe that the most important single social program in the country is being made a playtool of budgetary tinkering by the Carter administration.

The proposed Social Security cuts, unless changed at the last minute, are expected to include elimination of the children's benefit for survivors of a dead worker when the child reaches 18 (at present, benefits continue through 21 if the child is a full-time student), elimination of the $255 burial benefit, elimination of the $122-a-month regular minimum benefit and a reduction of maximum payments for a disabled worker.

Elizabeth Wickenden, a social welfare expert who once worked for Harry Hopkins in the Roosevelt administration, said yesterday, "Once you start using the Social Security benefits as a means of balancing the budget, you open up the whole program to manipulation."

Wickenden, in a fact sheet distributed by a study group she is forming with Cohen, National Urban Coalition Director Carl Holman and several others, said the old-age-and-disability-security structure so painstakingly constructed over the years to guard against destitution is being sacrificed "to reduce the overall 1980 federal budget deficit."