Faced with the possible passage of tough amendments to the Fair Housing Act next year, the National Association of Realtors has moved independently to strengthen its own commitment to affirmative marketing of all housing offered to the public.

Realtor national President Donald Hovde of Madison, Wis., said here recently that more than 60 percent of the membership of NAR now is under a commitment to avoid discrimination in the selling of houses and that the goal for 1980 is 80 percent.

Local boards of Realtors voluntarily adopt the affirmative marketing resolution, but it is the prerogative of individual brokers to sign. The four Realtor boards in the immediate Washington area have all endorsed the agreement that involves advertising properties as being available to any qualified buyer. However, some individual brokers decline to sign because they insist that it is merely a pledge to uphold a law that already binds them.

Hove and incoming NAR president Ralph Pritchard of Chicago said that Tom Sprewer, a Realtor and former director of HUD's model cities program in Milwaukee, has been named to head the NAR's new office of community programs to advance the commitment to equal access to housing for all persons and families.

Meanwhile, legislation has been introduced in both houses of Congress to provide an administrtative court system within the Department of Housing and Urban Development to handle charges of discrimination normally handled in the court system. Pritchard said that the fair housing amendment would make it more difficult for sellers, small lenders and brokers to defend themselves and also would deprive a winning litigant of any monetary award after a jury trial.

NAR has urged members of the House and Senate judiciary committees to consider amendments that would remove the proposed HUD administrative court provisions but allow HUD to initate investigations of discriminations rather than waiting for complaints to be filed. NAR backs the use of federal magistrates to hear charges of discrimination.

Additionally, NAR has sponsored the production of a film, Securing the American Dream, which deals with discrimination in the marketing of housing and also demonstrates how equal housing opportunities can be advantageous to neighborhoods. The film will be available for showing around the nation.