An Illinois congressman will ask President Reagan to pardon Oliver L. North and John M. Poindexter, two former White House aides indicted in the Iran arms affair, before Reagan leaves office, it was reported Saturday.

North and Poindexter "did what they thought was in the best interest of the country," Rep. Henry Hyde, R-Ill., told the Chicago Sun-Times.Such a move, said Hyde, "is not a not-guilty finding, it's not absolution, it's a pardon. It is saying that . . . `I forgive you.' "