A police officer may, with or without a warrant, arrest a person who is caught committing a criminal offence. They may also arrest persons where the police officer has reasonable cause to suspect the person has committed an offence or is about to commit an offence [see Summary Offences Act 1953 (SA) s 75; Criminal Law Consolidation Act 1935 (SA) s 271 for citizen power of arrest; and also commentary on the Cross-border Justice Act 2009 (SA) (below)].

An arrest is only valid if a police officer finds a person committing an offence, or the officer reasonably suspects a person has committed or is about to commit an offence. There is a substantial body of case law in relation to valid arrest procedures and the question of whether or not a person has been arrested rests on the facts of each case.

Generally, an arrest occurs when the police officer makes it clear (by words or by action) that the person is under arrest and is deprived of their liberty. Normally, in situations where it would be reasonable to do so, a police officer, should clearly inform the person of the reason for the arrest (the suspected offence) in a way the arrested person is able to understand [see Hull v Nuske (1974) 8 SASR 587at 594; and R v Conley (1982) 30 SASR 226 at 239 for examples of the underlying principles].

A police officer may arrest a person, without a warrant, who is suspected of having an outstanding warrant issued by a justice [see Summary Offences Act 1953 (SA) s 79]. A person who is arrested in accordance with a warrant issued by a justice does not have the same arrest rights as a person who is arrested under suspicion of having committed an offence. The arrested person must be warned that anything they say may be taken down and used in evidence, and they have a right to make a telephone call to inform someone of their whereabouts [see Summary Offences Act 1953 (SA) ss 79A(3)(b) and 79A(3)(a); the Rights of an Arrested Person (below); and Warrants chapter].

A police officer may arrest a person where there is reasonable cause to suspect the person has committed an offence in another state and where the offence would be an indictable offence or an offence punishable by imprisonment of two years or more had that offence been committed in South Australia [see Summary Offences Act 1953 (SA) ss 78A(1) and 78A(2); Criminal Investigation (Extraterritorial Offences) Act 1984 (SA) s 4 for issue of search warrants; and s 5 for authority under a search warrant].

Upon apprehension, the arrested person must be brought to the Magistrates Court as soon as reasonably practicable. The court may dismiss the charge, admit the person to bail, or commit the person to custody pending the issue of an interstate warrant for their apprehension and the execution of that warrant [see Summary Offences Act 1953 (SA) s 78A(3)].

Should a warrant for the apprehension of that person not be issued and executed within 7 days, that person must be discharged from custody or released from bail by the Court [see Summary Offences Act 1953 (SA) s 78A(4); and Warrants chapter].

A police officer may arrest and detain a person (without a warrant):

However, before arresting the person the police officer must first require the person to remain at a particular place for so long as may be necessary for the order to be prepared and/or served.

If the person refuses of fails to comply with the requirement or the police officer has reasonable grounds to believe the person will not comply, they may then arrest and detain the person.

This period of detention must not exceed a period of 2 hours unless approved by the Court. The Court may extend a period of detention to a total period not exceeding 8 hours [see s 34(4)].

A police officer may also arrest and detain a person (without a warrant) in conjunction with serving an intervention order if they believe on reasonable grounds it is necessary to prevent the immediate commission of abuse or to enable measures to be taken for the protected person(s) [see s 35].

This period of detention must not exceed a period of 6 hours unless approved by a Court. The Court may extend a period of detention to a total period not exceeding 24 hours [see s 35(2)].

Finally, a police officer may also arrest and detain a person (without a warrant) if they have reason to suspect a person has contravened an intervention order [see s 36].

The person must be brought before the Court not more than 21 hours after arrest (not including weekends or public holidays) [see ss 36(2) and (3)].

A police officer may arrest and detain a person (without a warrant) if:

Before arresting a person to effect service the police officer must first require the person to remain at a particular place for so long as may be necessary for the order to be prepared and/or served.

If the person refuses of fails to comply with the requirement or the police officer has reasonable grounds to believe the person will not comply, they may then arrest and detain the person in custody for the period not exceeding 2 hours [see s 99E(4)(a)(ii)].

A person arrested on suspicion of having contravened a restrainig order must be brought before the Court not more than 24 hours after arrest (not including weekends or public holidays) [see ss 99I(3) and (4)].

A police officer may arrest and detain a person without a warrant (but with the authorisation of a police officer above the rank of Inspector) if they reasonably believe that the person has breached a condition of parole, and:

If a police officer so arrests a person, they must notify the Parole Board within 12 hours. See Parole warrants.

See Correctional Services Act 1982 (SA) s 76B.

The Cross-border Justice Act 2009 (SA) applies within a defined geographical region at the intersection of the South Australian, Western Australian and Northern Territory borders [see Cross-border Justice Regulations 2024 (SA) reg 4 and Sch 1]. The provisions of the Act apply upon suspicion or allegation of an offence committed within the region, and/or when an accused is arrested in the region or normally resides in that region [see Cross-border Justice Act 2009 (SA) s 20(2)]. The provisions also apply for persons residing in the region at commencement of court proceedings [see s 20(3)].

Where a person connected with a cross-border region is suspected of having committed an offence or of having breached an order of this State, a South Australian police officer may investigate the offence or breach whilst in another participating jurisdiction and may exercise any police powers in accordance with the laws of South Australia [see s 35(1), (2)]. This includes powers to enter and search premises, the search of vehicles and people, interviewing people, and the taking of photographs, prints and samples [see s 35(3)]. A police officer from another participating jurisdiction may investigate an offence or breach of an order from their jurisdiction whilst in South Australia and may exercise any powers of a police officer from his or her jurisdiction [see s 52(1), (2) and (3) for police powers]. A South Australian Magistrate or a Magistrate from another participating jurisdiction may issue a warrant for the purpose of investigating an offence or a breach committed by a person connected with a cross-border region [see ss 35(4) and 52(4)].

A South Australian police officer may, with or without a warrant, arrest a person whilst in another participating jurisdiction within the geographical region (namely Western Australia or Northern Territory) [see ss 32 and s 33(1); and Bail Chapter]. Where a South Australian police officer arrests and detains a person in another participating jurisdiction within the geographical region, the laws of South Australia apply in relation to the custody of that person [see Cross-border Justice Act 2009 (SA) s 34(3)]. Where a police officer from a participating jurisdiction arrests and detains a person, with or without a warrant, who is located in the South Australian region, the laws governing the arrest and custody of a person from that police officers jurisdiction apply [see ss 49, 50(1), 51(2)(b) and 51(3)]. A South Australian Magistrate may issue a warrant for the arrest of a person located in another participating jurisdiction where that person has a connection with a cross-border region in accordance with South Australian law [see s 33(2)]. A Magistrate of another participating jurisdiction may issue a warrant for the arrest of a person located in the South Australian portion of the region in accordance with the laws of the participating jurisdiction [see s 50(2)].