Fatigue is more than feeling tired and drowsy. In a work context, fatigue is mental and/or physical exhaustion that reduces your ability to perform your work safely and effectively.
The causes of fatigue can be work-related, personal or both.
Persons conducting a business or undertaking (PCBUs), such as employers, must eliminate or minimise the risk of fatigue, so far as is reasonably practicable.
Workers also have a duty to take reasonable care for their own safety and health and make sure their acts or omissions don’t adversely affect the health or safety of others.