Pope John Paul II today issued the third encyclical of his three-year pontificate, an analysis of the modern world's labor situation that calls for greater social justice and fuller participation of workers in management and the fruits of production.

It addresses the issues of unemployment and working mothers and calls for fairer treatment of handicapped and migrant workers. While stressing the right of women to equal employment, the document urges that "a family wage" be paid to fathers or grants be given mothers so that the mothers could remain at home to meet the needs of the children.

The 24,000-word encyclical --entitled in Latin "Laborem Exercens," and in English "On Human Work"--was prepared by the pope last spring and revised by him during his recuperation from wounds suffered in the attempt on his life last May.

Encyclicals, which are papal pastoral letters, have traditionally been used by popes to address the world's 600 million Roman Catholics on major doctrinal, moral and disciplinary issues and to apply Roman Catholic teaching to social matters. While they are not held to be infallible, they carry strong papal authority to which, in the view of most theologians, Catholics are expected to assent.

A high-ranking Vatican official said today that the goal of the scholarly and complex papal document, John Paul's most sweeping socio-political statement so far, was that of inspiring new concepts that could both unite workers and heal persisting divisions between labor and capital.

While the encyclical did not mention current political problems in Poland that have grown out of the establishment of Solidarity, the independent labor union, it was amply sprinkled with the word "solidarity" and contained an impassioned defense of independent labor movements. It thus was seen by some analysts as reflecting and bearing special relevance to the pope's native Poland, where workers are involved in a bitter struggle for greater rights.

"In order to achieve social justice in the various parts of the world, in the various countries, and in the relationship between them," the encyclical said, "there is a need for ever new movements of solidarity of the workers and with the workers."

John Paul, who has frequently expressed strong support for Poland's Solidarity movement and who met here with its leader, Lech Walesa, earlier this year, described unions as "a mouthpiece for the just rights of the working peoples" and said strikes, a burning issue in contemporary Poland, are "legitimate in the proper conditions and within just limits."

But he cautioned that the proper role of a union is not to "play politics" and that a strike, which he defined as "an extreme instrument" that must not be used to disrupt community services and ought "not to be abused, especially for political purposes."

The portion of the encyclical dealing with salaries called for "just remuneration for the work of an adult who is responsible for a family."

It proposed either "what is called a family wage--that is a single salary given to the head of the family for his work, sufficient for the needs of the family without the other spouse having to take up gainful employment outside the home," or "other social measures such as family allowances or grants to mothers devoting themselves exclusively to their families."

The encyclical contained no specific guidelines for carrying out such a program but said the compensation should correspond to the family's actual needs and the number of dependents.

"The true advancement of women," it said, "requires that work be structured in such a way that women do not have to pay for their advancement by abandoning what is specific to them and at the expense of the family in which women as mothers have an irreplaceable role."

The pope criticized the excesses of both Marxist-inspired collectivism and what he termed "rigid capitalism." Society ought to focus on worker participation, he said, and in general this means creating a system based on "associating labor with the ownership of capital."

"Laborem Exercens" was published to coincide with the 90th anniversary of "Rerum Novarum," the landmark encyclical issued in 1891 by Pope Leo XIII to deal with the widespread social and labor disruption caused by the Industrial Revolution.

In the introduction to his 99-page encyclical John Paul said the present era was marked by "new developments in technological, economic and political conditions which, according to many experts, will influence the world of work and production no less than the Industrial Revolution of the last century."

He listed these as "the widespread introduction of automation," pollution, the limited "heritage of nature" and the emergence of underdeveloped nations, and said these new conditions would require "a reordering and adjustment of the structures of the modern economy and the distribution of work." For many skilled workers, he said, the result will be unemployment and the need for retraining.

The pope said that while it was not the place of the church to analyze the possible consequences of these developments, the church hoped that, by calling attention to the dignity and rights of those who work, it could "guide the above-mentioned changes so as to ensure authentic progress by man and society."

The Rev. Jan Schotte, secretary of the Vatican's Justice and Peace Commission, said at a news conference today that the encyclical was a synthesis of the pope's statements during his various trips abroad during which, as here, he has frequently spoken out in favor of greater social justice and has condemned conditions producing poverty, hunger and worker exploitation.

The encyclical seeks, through an analysis of the nature of work, to explain the intricate relationship between labor and capital, which the pope said are "inseparably linked." Since both capitalism and collectivism have failed to solve the problem of work--defined by the pope as "one of the characteristics that distinguish man from the rest of creatures, whose activity for sustaining their lives cannot be called work"--an alternative, he said, might be worker association with capital ownership.

The first part of the encyclical is devoted to the ethical aspects and dignity of work, the value of which, it says, "should be measured by the same standard and not according to differences in nationality, religion or race."