Although a strike by the Washington Teachers Union was narrowly averted through a last-minute agreement Tuesday, the underlying issues continue to be a growing source of friction between the D.C. School Board and the union and could produce a strike at any time.

The school board has made it known that it is unhappy with concessions made to the teachers in past contracts and is determined to remove some of them during the upcoming contract talks. But the union has made it clear that it does not intend to give away any of the gains made in past years and will bargain for more in the forthcoming contract talks.

Contracts negotiatied by the teachers union for its members in the past have made Washington teachers the highest paid in the metropolitan area and given them the shortest work day and the shortest school year.

School board president Conrad Smith has said that because the teachers are well paid they should be willing to spend more time in school and improve the test scores of Washington school children, which fall far below both national norms and test scores from other big cities.

"Oh, not that again," said union president William P. Simons when he was asked about the Washington teachers being the highest paid in the area. "How long has it been since teachers gained a fair salary? Not long ago bus drivers made more than teachers even though a teacher had to have four years of college. . ."

Out of those opposing positions have come several specific issues about which the board and the union differ:

Lenthening the school year.

Extending the number of hours teachers have to be in school.

Changing the grievance procedure for teachers to make it easier for school administrators to get rid of bad teachers.

Changing the rules governing pregnancy leave and sabbaticals to force teachers to return to school at the start of the school year, in the middle of semesters, or at the end of the term to avoid switching teachers in classes in the middle of a course.

Conrad Smith, president of the D.C. school board, said yesterday he expects to bring all of those proposals to the bargaining table when talks between the union and the board begin Oct. 16.

"I don't think its a matter of (The teacher's union) giving up anything for the union to agree to the proposals during the negotiations," said Smith. "The teachers' union has got to understand the importance of improving the conditions under which teachers work and teach . . . we should all be trying to improve the schools."

But Simons has opposed some of the same proposals Smith is determined to make school policy in previous contract talks.

"I think you'd be right in saying we are pleased with the contract we have right now," Simons said. "We're going to the negotiations to bargain for just as much or more. Unless the board is willing to give us something that we don't have now I don't see why we should be expected to give up we've had . . ."

Since 1969 when Washington's first elected school board took office, the board has been trying to cut back on the rights and powers of the city's teachers. The board has had difficulty in making gains in contract talks with the union because the board does not control the teacher's salaries. Teachers' wages are set by the City Council and the congress.

On the average, D.C. teachers earn over $1,000 more annually to begin working in the District of Columbia than teachers in Montgomery and Fairfax counties. D.C. teachers are paid $11,824 to start after earning a bachelor's degree and the top of their pay scale, for persons with a bachelor's degree, is $19,765.

In Montgomery County, public school teachers earn $10,479 for a beginning teaching job, with a bachelor's degree.

The highest step in the Montgomery County pay scale for teachers who have a bachelor's degree is $16,636.

In Fairfax County, teachers in public schools start at $10,500 annually. At the top of their pay scale Fairfax County teachers earn $19.120.

In terms of the length of their school day, D.C. teachers work 6 1/2 hours a day, in comparison with a 7 1/2 hour day for teachers in Fairfax and Montgomery counties.

Washington also has the shortest number of days in its school year with 182 teaching days, as opposed to 190, in Fairfax and 191 in Montgomery.