The most appropriate approach for internal audit activity to follow up on management action plans is to create a tracking system. This ensures that follow-up activities are systematically monitored and documented. Such a system can track the status of action plans, provide reminders for due dates, and record progress updates, thus ensuring that management's corrective actions are implemented and effective. Regular monitoring and tracking are essential to verify that issues identified in audits are addressed in a timely manner.
Reference:
Institute of Internal Auditors (IIA) Standards: Implementation Standards 2500 - Monitoring Progress COSO Framework: Monitoring Activities Component