A trespasser is someone who enters onto land without invitation or implied permission.

Excessive force cannot be used to remove a trespasser as this is an assault. A better course of action is to call the police and later sue the trespasser for compensation for any damage caused.

In some situations it may be appropriate to apply for an intervention order to prevent a person from trespassing again [Intervention Orders (Prevention of Abuse) Act 2009 (SA) ss 6, 8].

The police can be called to remove trespassers who will not leave when told to or, who return within twenty four hours. The police can prosecute the trespasser who faces a penalty of up to $2500 fine and imprisonment for up to six months [Summary Offences Act 1953 (SA) s 17(a)].

A trespass can also be committed by causing an object to cross over onto a neighbouring property, for example, firing a gun at a cat on the neighbour's roof.

A neighbour who throws rubbish over a boundary commits an offence and is liable to a fine up to $750 [ Summary Offences Act 1953 (SA) s 57].

An uninvited person or gatecrasher at a party can also be guilty of trespass if they fail to leave when requested to do so (see Children and Young People)