A teacher's relationship with a student is based on the fact that, while the child is at school, the teacher is in loco parentis (that is, the teacher takes over the role of the parents) and is entitled to use the parents' authority to carry out his or her duties in relation to the child.
In government schools a teacher's right to discipline a pupil is governed by the Education Act 1972 (SA) and the regulations made under the Act, which give school principals the authority to impose controls on the behaviour of students and to apply penalties for breaches of school rules.
The head teacher of a government school has broad powers to suspend, exclude or expel a student who has, for example, threatened or perpetrated violence; or has acted in a manner that threatens the safety or well being of other persons at the school or has acted illegally, or has acted in a manner that threatens the good order of the school [Education Regulations 2012 (SA) r 44-46]. Physical punishment was phased out of government schools in 1991 and can no longer be administered. However, teachers can detain students during their lunch break and after school hours [Education Regulations 2012 (SA) r 43 ].
In non-government schools it is the governing body of the school that makes the rules for discipline and the type and manner of penalty for the breaking of those rules. A teacher who inflicts physical punishment on a child when not properly authorised to do so, or who uses excessive force in doing so, may be committing assault.