Negotiators for the Washington-Baltimore Newspaper Guild and The Washington Post have reached tentative agreement on a new wage and fringe benefit package that would end more than three years of portracted talks.

The proposed contract, agreed to at 4:30 Thursday morning and recommended unanimously last night by the guild's unit leadership committee, is still subject to a July 10 membership vote.

The agreement calls for pay increases totaling up to $82 a week over the next three years, plus provisions for cost-of-living increases in the second and third years of a three-year contract. The raises are retroactive to April 1.

In addition, the proposed contract involves a restructing of the paper's health and pension funds in order to buttress employe benefits that have been in financial jeopardy. And for the first time, the paper's part-time employes would become eligible for health benefits. Part-time employes make up about one-fifth of The Post's work force.

The guild represents editorial, sales and clerical employes. About 550 of the approximatley 1,000 Post people covered in these groups are dues-paying members of the union.

Negotiations between the union and The Post have been sporadic since expiration of the old contract in March 1976. Serious talks began in the spring.

To reach a compromise, the guild negotiating team yielded on the issue of union security. It gave up what had been a requirement that 8 out of 10 new hires join the guild. Since 1976, however, that requirement has been abandoned.

The guild also agreed to abide by eventual National Labor Relations Board rulings on whether about 160 mid-level editorial staffers are eligible for guild membership.

In return, the company agreed to withdraw its demand for a no-strike clause in the new contract.

"We're glad to be able to take something we can recommend back to the membership." said Charles Babcock, cochairman for The Post guild unit.

Lawrence Wallace, the Post's vice president for labor relations said: "Ater almost three years, it a relief to have reached a tentative settlement. The contract is very fair to the employes, to The Post and to the guild. Hopefully, this will usher in an era of good relations."