In general terms, 2-3 hours per day is a guide. It would not be recommended for a child or young person to spend more than half their day in front of a screen, keeping in mind all forms of screen-time, such as television and games. In many cases, students will use their device for stimulus, while completing work on paper rather than on the device.
The eSafety Commissioner provides detailed resources and information to parents to assist them in deciding the appropriate amount of screen time for their children, as well as other information about avoiding online dangers and cyber bullying.