SAN FRANCISCO (AP) _ Larry Brinkin couldn't take a leave from his job after the death of his homosexual lover of 11 years, but a proposed law would give him and other city employees the same bereavement leave as married couples.

The measure proposed Tuesday effectively would redefine the family by legally equating homosexual and unmarried relationships with marriage for 24,000 municipal employees.

''The legal world must reflect the realities that exist in our private existences,'' said Supervisor Harry Britt, who wrote the ''domestic partnership'' legislation. ''Both gay people and unmarried heterosexuals have been denied the fundamental right to live in love and happiness.''

A narrower version of the legislation was vetoed by then-Mayor Dianne Feinstein in 1982. She called it too vague.

But this time, Mayor Art Agnos endorsed the measure from the start and eight members of the 11-seat Board of Supervisors signed on as co-sponsors. The ordinance will be heard before a city committee on May 11.

If approved, it would be the most far-reaching measure of its kind, although three California cities, Berkeley, Santa Cruz and West Hollywood, allow municipal employees to add partners to health benefit and pension plans.

The ordinance would ban discrimination by any city agency against people because of the non-traditional relationship status. It also requires that steps be taken to extend many benefits to people in committed relationships that now are provided only to married people, including dependent health care and legal standing in housing contracts.

''The message is that San Francisco is a place where it is understood that the family unit, even if it is non-traditional, is paramount to our lives in terms of our survival, the support we need, to keep us free from loneliness, to help us economically,'' said Brinkin, who unsuccessfully sued his former employer, Southern Pacific, over the denied leave.

Although the ordinance would not apply to the private sector, the San Francisco Chamber of Commerce announced it would begin a study of the issue with the aim of informing businesses what benefits they should offer employees in such relationships.

Britt's measure would require domestic partners to have a joint home and to share basic living expenses, although each could maintain a second home. They also must register with City Hall or, for those wishing confidentiality, with a notarized statement filed with an independent third party, such as a private attorney.

The measure has been criticized by some religious groups.

The San Francisco Roman Catholic Archdiocese will not support ''any effort to weaken the institution of marriage, to tinker with it, or put any parallel system alongside it,'' said spokesman Norman Phillips.

But Tom DiMaria, of the Washington-based National Gay and Lesbian Task Force, called domestic partnership a ''fundamental requirement'' for homosexuals to be accepted by society.

''This tells people that gay and lesbian relationships are a viable, healthy and acceptable new form of the traditional family,'' DiMaria said.

The measure directs a city task force to examine all city policies and practices to identify those that put non-married couples at a disadvantage.

Eventually, homosexual and unmarried heterosexual partners could have legal standing in real estate and rental contracts and could become eligible for rental and housing programs offered now only to traditionally families. Sick leave for city employees whose lovers or parents are seriously ill also would be expanded.

Partners also would have hospital and jail visitation rights similar to traditional family members.

By city charter, supervisors can only ask the city's Health Services System, an independent agency that runs city hospitals, clinics and health benefit programs, to extend benefits to domestic partners. With Agnos as mayor, Britt hopes the department's compliance will be routine.

If adopted, San Francisco would be the only major metropolitan city with such a measure. Several other cities, including Washington, D.C., and Madison, Wis., currently are studying the issue.

West Hollywood, which has a large homosexual population, also offers a domestic partnership certificate, and 219 couples have registered since 1985.