The D.C. Council's Government Operations Committee approved legislation yesterday that would limit the mayor to two consecutive terms and limit council members to three consecutive terms.

Several council and staff members said the measure is likely to be passed when it is considered by the full council this fall. They cited growing public support for limitations on terms for public officeholders. Currently there are no such restrictions on D.C. elected officials, who serve four-year terms.

Both Democratic mayoral nominee Sharon Pratt Dixon and Republican nominee Maurice T. Turner Jr. have expressed support for limiting the term of mayor.

Outgoing Mayor Marion Barry, who once opposed limiting the term of the mayor, said in a letter to the council yesterday that he now supports the concept.

"It is a tough one to vote no on," said council member William Lightfoot (I-At Large). "I think most people in the city would be in favor of limiting the terms of council members . . . . I don't think any one of us is so unique that we're irreplaceable."

Lightfoot and other supporters of the measures also argued that the term limits would open up the political process in the District to new leadership by correcting what they described as an unfair electoral advantage enjoyed by incumbents.

In other action, the Barry administration told committee members that it supports a proposal to extend health and other employee benefits enjoyed by the spouses of District workers to unmarried "domestic partners" of city workers.

The proposal has been one of the most highly prized legislative goals of Washington's homosexual community, although proponents also stress that it would affect numerous unmarried heterosexual couples who do not now receive the same kind of benefits that married couples receive.

If eventually approved by the council, the proposal would make the District one of a few jurisdictions in the country that extends benefits in such a manner. Others include Seattle, Madison, Wis., and Berkeley, Calif.

Under the proposal by a commission consisting of gay rights leaders, city officials, labor leaders and others, such benefits would be phased in over five years.

Council member Betty Ann Kane (D-At Large), chairman of the Government Operations Committee, said she plans to introduce the necessary legislation to implement the program before the council recesses for the year.

"The nature of family and relationships has changed," Kane said. "People need to be treated equally, no matter what type of relationship they are in."

In a start toward implementing domestic partner legislation, the council recently approved a bill permitting city workers to use unpaid leave time to take care of ill family members, including gay or lesbian partners. The mayoral commission recommended that the city immediately extend other leave provisions to domestic partners.

The plan also calls for the city to develop a system for registering and dissolving domestic partnerships by the beginning of 1992, and to complete a study on the number of employees registering as domestic partnerships by 1993. Health benefits and other employee benefits would be extended by 1994.

The term limitation bill approved yesterday was introduced by council member Frank Smith Jr. (D-Ward 1), who intended only to limit to two the number of consecutive terms served by the mayor. There are 27 states and eight major American cities, including San Francisco, Atlanta and New Orleans, that limit the number of terms their chief executive can serve.

But council member Nadine P. Winter (D-Ward 6), who was defeated after four terms, offered a surprise amendment that also sought to limit council members to two terms, saying that she has received dozens of telephone calls from constituents supporting such a limitation.

Most of the members of the council have served more than two four-year terms. John A. Wilson (D-Ward 2), Chairman David A. Clarke (D) and Winter have served on the council for 16 years, although Clarke has been council chairman for only eight years.

Under the proposed legislation, terms as council chairman would be counted separately from terms as council members. D.C. council members are paid $71,885, the chairman receives $81,885 and the mayor's salary is $97,005.

Wilhelmina J. Rolark (D-Ward 8) has served for 14 years; Hilda H.M. Mason (Statehood-At Large) for 13 years; Kane for 12 years; John Ray (D-At Large) and Charlene Drew Jarvis (D-Ward 4) for 11 years; H.R. Crawford (D-Ward 7) for 10 years; and Smith for eight years.

Members of the Government Operations Committee staff said they were not aware of any other state legislature or municipal council that has such term restrictions.

Voters in Oklahoma recently approved the country's first term limitation measure for state legislatures, adopting a 12-year limit for state senators and representatives.

At first, Winter's amendment seemed destined for defeat, as Kane, Lightfoot and Jarvis argued that the committee should first hold a hearing on the issue.

But the fifth committee member, Ray, arrived late and made a forceful argument in favor of limiting council members to three terms. "We're talking about opening up the process," Ray said. "I don't think any of us ought to be professional politicians, and do that for the rest of our life."

Winter agreed to alter her amendment to a three-term limitation, and at that point, the tide seemed to change in favor of her action.

Smith, who is seeking a third term, said limiting council terms is unnecessary because the council already undergoes sufficient turnover. He pointed out that when the new council takes office in January, none of the members of the first home rule council in 1975 will remain in their seats. Wilson, who will be the only remaining member, is the Democratic nominee for council chairman.

But Winter's amendment was approved 4 to 1, with Winter, Ray, Jarvis and Lightfoot in favor and Kane opposed. Smith is not a member of the committee.

The restrictions on council terms would not apply to terms to which incumbents have already been elected.