Washington school superintendent Vincent E. Reed announced yesterday that the school system would delay for at least a year the introduction of its new competency-based curriculum because developing it and making sure it works are taking more time than expected.

"We found out that we haven't progressed as far as we planned in developing the new curriculum ("Reed said, "I just don't want to blunder into it . . . We have to make sure it teaches what we say it does. We don't want to blow it."

Reed made his announcement at the start of a two-day conference on the new curriculum, which is supposed to spell out step-by-step how major subjects will be taught in every school in the city.

The confernece, attended by about 350 teachers and administrators, is at Dunbar High School.

According to plans Reed announced in 1976, the new curriculum was expected to be used in all the city's 180 schools - from kindergarten through 12th grade-starting next September.

In addition, the D.C. school board approved plans for setting minimum achievement standards for high school graduation and for promotion from grade to grade. The standards would be enforced by system-wide exams.

This year parts of the new curriculum, which includes a required series of tests, have been used on an experimental basis in 29 schools.

But Reed said preliminary reports from evaluators indicate that substantial changes must be made to ensure that the curriculum is effective.

Next year, Reed said, the revised curriculum will be used in about 50 Washington schools, and research on its effectiveness will continue. He said the curriculum probably would be used system-wide, starting in September 1979.

"That's what we're pushing for," Reed said. "I'm certainly going to try. But I'm not absolutely sure we're going to do it . . . You know, in the past we've been accused of jumping into things without thinking them out.

Reed added that he hoped to develop specific promotion and graduation standards within two years, but was uncertain when they would be enforced.

At the conference yesterday, associate superintendent James T. Guines, who has been in charge of drawing up the new program, said the school system hopes to drop the pattern of placing children in well-defined grades (such as first, second, and third) for a whole year.

Instead, Guines said, there should be a system of "continuous progress," in which students move ahead in different subjects based on how quickly they pass test to demonstrate that skills along a well-defined sequence.

"That's going to take a whole lot of attitude change on the part of parents and teachers," Guines said. "We cannot wait until once a year every year to make that hard decision - promotion or retention."

William G. Spady, a researcher for the National Institute of Education who has been a full-time consultant to the D.C. schools this year, strongly backed the "continuous progress" idea.

But Spadly said it might be difficult to enforce the new sustem with slow learners when students reach the ageat which they traditionally move on to new schools, such as going from elementary school to junior high or from high school to college.

Spadly suggested that whenever students leave high school, they should be given "a content-based diploma" containing a detailed record of the skills they have developed, but not requiring a minimum level of achievement.

Another speaker, James H. Block, and eduction professor at the University of California at Santa Barbara, said he was concerned that competency-based curriculums in Washington and elsewhere would be too narrowly based and mechanistic.

However, Sarah Banks an algebra teacher at Gordon Junior High School, 35th and T streets NW, complained that now, without clear standards, half the students in her elementary algebra class cannot do the work.

Bnaks said she wanted to keep out students who had not mastered basic math skills, but that school administrators said such youngsters had to be let into the algebra class if parents wanted them to take it.

Reed said eventually he hopes all students would have skills needed to study algebra before they take the course. But he added: "I don't think in this city from a realistic standpoint, a youngster should be excluded from algebra now if he wants to try it.