How can HR manager Steve enforce discipline at the workplace

Steve, an HR manager, is in a difficult situation. He has made repeated attempts to get employees to maintain work timings, but he has failed. He sent circulars to department heads, but only some department heads have implemented the policies. Steve even notices that a few department heads flout the rules. When Steve requests the department heads to implement corrective measures, few take him seriously. Analyze how Steve and his team can enforce discipline at the workplace by addressing each of his issues.