The Boston School Committee and the National Association for the Advancement of Colored People fought another inconslusive battle last night in their continuing dispute over the existence of de facto segregation in the city's schools.

But it appeared the NAACP was prepared to make a decisive new move against the Committee. Association leaders will meet this morning to map out final plans, but most likely they will bring a suit against the School Committee. Unlike many other states, the Massachusetts state commissioner of education lacks the power to ban, by decree, racial imbalances in public schools.

The projected one-hour meeting between the two groups broke up after only 18 minutes last night, when chairman Louise Day Hicks ruled NAACP representatives out of order for attempting to discuss de facto segregation. Amid the glare of television lights, the NAACP members walked out of the packed meeting room on the third floor of the School Committee building, 15 Beacon St.

The walk-out was not very surprising to the audience. Two weeks ago the School Committee agreed to meet with the NAACP to discuss "educational matters." The Committeemen made it very clear they do not consider de facto segregation an educational issue.

Two days later the NAACP accepted the invitation to meet, and listed de facto as the first topic it would like to discuss. Thus the scene for last night's walk out was set long ago.

One of the NAACP's national experts on educational matters attended the meeting last night, and afterward charged that the Boston School Committee was the only such board in the country to refuse to recognize the existence of de facto segregation in its school system.

The Committee's stand is that racial imbalances in the school system is a "neighborhood problem" not under its purview. The NAACP retaliates that the problem exists; that it has harmful affects on Negro children, and that it is the Committee's duty to deal with it. The Association makes it clear, however, that it does not believe the Committee is responsible for the racial imbalances in Boston.

In addition to legal suits it is considered a distinct possibility that the NAACP will stage a massive demonstration in front of the School Committee offices in support of its position.

Throughout the battle observers have sensed a restiveness among NAACP members to challenge the Committee with such a march. One was planned for last week before the Committee agreed to hear NAACP grievances last night.