The formal charge of an offence is called an Information. Prior to 3 October 2017 the formal charge of most summary offences was called a Complaint.
An Information can be laid personally or by a legal practitioner, or other person duly authorised to lay the information on the informant's behalf. For a summary offence that can be done by going to the Magistrates Court and saying to a Registrar, Deputy Registrar or justice of the peace that an offence has been committed [Criminal Procedure Act 1921 (SA) s 49; Magistrates Court Rules 1992 (SA) r 12.02].
For summary offences the time limit within which to issue an information is six months if an expiation notice has be given for the offence (from the expiry of the expiation period specified in the notice) but for any other summary offence the time limit will be two years (of the date on which the offence is alleged to have been committed) [Criminal Procedure Act 1921 (SA) s 52].
A private citizen who lays an information must carry on the prosecution. However, most prosecutions for summary offences are begun by, and in the name of, the police. The prosecution is conducted either by a police prosecutor or a lawyer employed by the police. Certain government departments and agencies, such as the Department of Transport, Energy and Infrastructure and Consumer and Business Services, the Department of Primary Industry and Fisheries, Safework SA and others employ their own legal officers or use lawyers from the Crown Solicitor's Office for this purpose, for example for prosecutions in relation to fisheries and native vegetation offences.
The police have considerable discretion in deciding whether or not to prosecute a complaint. Although it may strongly appear that a person is guilty of an offence, it is the job of the prosecutor to consider the available evidence and they may decide not to go ahead with the charge for a number of reasons, such as: