A former assistant secretary for the U.S. Department of Housing and Urban Development and a high-ranking union official were indicted here yesterday on bribery and lying charges, respectively, in connection with an alleged scheme to sell group automobile insurance to labor unions.

Charged in the bribery case was Charles T. (Red) Muntain, 56, of Crofton, Md., former assitant HUD secretary for labor relations, who allegedly received more than $2,500 in cash, a sailboat, a microwave oven, trips and other benefits for allegedly endorsing the scheme.

Named in a separate indictment was Charles E. Nichols, 56, of Alexandria, general treasurer of the 850,000-member United Brotherhood of Carpenters and Joiners of America, who allegedly lied about his knowledge of Muntain's involvement in the scheme.

The charges were brought by U.S. grand jury, whose term expired yesterday, that has been probing alleged ties between certain government officials and members of organized crime along the East Coast.

The charges against Muntain allege that he entered into a conspiracy with Kellopp lobbyist Deryl E. Fleming and California businessman Charles A. Cordial to meet with labor union officials and endorse the mass marketing of group automobile insurance plans to labor unions. The plans would then be offered to employes as fringe benefits in labor contracts, investigators said.

In return for his assistance in meeting the labor officials, which he knew largely through his role as the top labor relations official at HUD, Muntain would received a sailboat, golf clubs, a microwave oven, plane trips, and expense payments from various persons, according to the indictment.

Muntain is charged in the 13-count indictment with conspiracy, receiving illegal gratuities, receiving payments from someone other than the U.S. government for which he was employed, and making false statements to the federal government by refusing to disclose to HUD his involvement in the goup automobile insurance scheme.

The three-count indictment against Nichols charges him with lying to the grand jury concerning his dealings with Muntain, Fleming and Cordial in connections with the automobile insurance plan.

In that testimony, as recounted in the indictment, he denied meeting with Muntain and said he had no knowledge of Muntain's involvement with the automobile insurance plan.

The only other person charged so far in the continuing investigation is Cordial, who pleaded guilty to obstruction of justice and was placed on probation for three years.