Each State and Territory in Australia provides statutory permission for ordinary members of the public (not limited to actual citizens) to make an arrest without a warrant, if it is patently obvious that a person has committed an unlawful act. While each jurisdiction provides notable variation, there are clear conceptual overlaps enabling a lot of discussion of this power concerning all jurisdictions at once. The definition of arrest is unitary across the jurisdictions, as is the concept that the purpose of the arrest is to hand the suspect or offender over to police.
The power of citizen's arrest tends to be understood by the security guarding industry in a fairly basic manner. This section sheds further light on the matter, identifying both restrictions and liberties not commonly understood.
The relevant statutory provisions are as follows:
Australian Capital Territory – Crimes Act 1900, section 218;
New South Wales – Law Enforcement (Powers and Responsibilities) Act 2002, section 100;
Northern Territory – Criminal Code Act 1983, section 441;
Queensland – Criminal Code Act 1899, section 546;
South Australia – Criminal Law Consolidation Act 1935, section 271 (See also Summary Offences Act 1953, section 77);
Tasmania – Criminal Code Act 1924, section 27 (see also Appendices A and B);
Victoria – Crimes Act 1958, sections 458 and 462A;
Western Australia – Criminal Investigation Act 2006, section 25.
Is Committing or Has Committed - Arrest for Attempted Crimes?
The above provisions, except in Victoria, expressly allow for a private person to effect an arrest of a criminal offender who either has committed, or is in the process of committing, an offence. This means that there is no need for the common practice of retail security operations to wait for a shoplifter to depart from the store with the goods they are stealing before affecting an arrest. The notion that an arrest within the store is a false arrest ignores important wording of the statutes. If the evidence of the offender’s behaviour after acquiring goods surreptitiously – in particular their avoidance of the checkout queue – shows clearly an intention to steal, then they can be arrested while still within the premises. It remains common sense, however, to wait until the theft is fully committed due to the potential for an absent-minded person to take goods toward the exit negligently, and because if the person is prevented from exiting the store, then the only crime they can be charged with is attempted theft.
In Victoria there is no express allowance to make an arrest for a crime having been completed, but only for a crime in the process of commission. (This can include attempts and ongoing crimes). That this wording should be taken strictly is shown in the contrast with the next section (s 459) which confers powers on police and Protective Service personnel to make arrests for crimes having already been committed.
Having worked in security in Victoria, this author is not aware of any person or company seeing any problem with a citizen’s arrest for a crime completed before the arrest. It may be said that a court, adopting the guidance of well-established common practice (as sometimes occurs with a lack of precedent), will permit the statute to be interpreted such that if a person is seen committing a crime, there is no reason why they cannot be arrested subsequently after the crime is complete, and that the extra power given to police is there to permit arrest on the evidence of witnesses alone. If a court gives a ruling concurring with this position, however, it could potentially support rulings in other jurisdictions that broaden the power of citizen’s arrest to resemble police arrest without warrant. Therefore legislative reform in Victoria is a better option than jurisprudence to define this power properly.
Whether the power of citizen’s arrest extends to all forms of attempted crime, however, needs further consideration. It depends on the nature of the crime whether any attempt at committing a crime is the same as being in the process of committing it. An affray is an example of a crime that is fully committed as soon as the act commences, even if it will go on for a few minutes. A citizen seeking to arrest the guilty party(ies) does not have to wait until it is over. But the wording of the statute does not exclude arresting an offender when taking steps in commencement. It is plausible, though, that the steps taken must, at a glance, obviously lead to a specific offence.
If a person arrives at a locked premises at night fully prepared for burglary and looks for a way to break in, they can be said to have attempted a burglary, but they have not commenced the commission of the crime. Anywhere except Tasmania where an express allowance exists, a citizen’s arrest would be a false arrest in these circumstances unless the person was already trespassing on private land outdoors. However if the said offender approached a door or window in an obvious attempt to break in, then a citizen’s arrest for attempted burglary would be lawful. An assailant approaching a person with a knife can be arrested before they manage to hurt the proposed victim. So too a shoplifter can be arrested en route to exit a retail store they intend to steal from, before having finalised the unlawful taking of goods by exiting into a public space.
 Crimes Act 1958 (Vic), s 458.
 Criminal Code Act 1924 (Tas), s 27(7).