Right to Know Grounds of Arrest in Western Australia
Reviewed by the Commoner Law Editorial Team. Sourced from Commonwealth Acts of Parliament, federal regulations, and official government guidance. State-level information reflects each state's own Acts and court decisions. Written in plain language for general understanding — this is educational content, not legal advice. Our editorial standards
What is this right?
Under section 3W of the Crimes Act 1914 (Cth), an AFP officer may arrest without a warrant only on reasonable grounds to believe you're committing or have committed a Commonwealth offence — and only where arrest is reasonably necessary for a defined reason (court appearance, preventing further offences, preserving evidence, and so on).
At the time of arrest, the officer must tell you the grounds. That's a common-law requirement going back to Christie v Leachinsky, reinforced by s. 23F of the Crimes Act, which requires the caution and the information about your rights to be given on the spot.
If the officer doesn't tell you why, the arrest may be unlawful. An unlawful arrest can lead to evidence being excluded at trial and a civil claim for wrongful arrest. Australian courts treat the requirement seriously.
When does it apply?
This right applies whenever an Australian Federal Police officer arrests you for a Commonwealth (federal) offence.
- It covers offences under federal laws such as the Crimes Act 1914, the Criminal Code Act 1995, drug importation laws, and fraud against the Commonwealth.
- It applies to all people in Australia, including citizens, permanent residents, and visitors.
- State and territory police have similar obligations under their own laws, but this right specifically covers federal arrests.
What to Do If Australian Federal Police Arrest You Without Explaining Why
- Ask clearly: "Why am I being arrested?" and "What offence am I being arrested for?"
- Listen carefully to the officer's response and try to remember or write down their exact words.
- Ask for the officer's name and badge number.
- Stay calm and cooperate physically while noting any concerns.
- Ask to speak to a lawyer as soon as possible.
What should you NOT do?
- Don't physically resist the arrest, even if you believe it is unlawful. You can challenge it later in court.
- Don't argue or become aggressive — this can lead to additional charges such as obstruction/resisting a Commonwealth official under s 149.1 of the Criminal Code Act 1995 (Cth) (maximum 2 years imprisonment). Note: s 7A of the Crimes Act 1914 does not create a resisting arrest offence.
- Don't assume you must answer questions just because you have been arrested — you still have the right to silence.
- Don't sign anything or make a statement before speaking with a lawyer.
How Western Australia differs from federal law
In Western Australia, arrest powers are governed by the Criminal Investigation Act 2006 (WA) (CIA), which consolidated and modernised police powers previously scattered across multiple statutes.
- Under section 128 of the CIA, a police officer may arrest a person without a warrant if the officer reasonably suspects the person has committed, is committing, or is about to commit an offence, and the officer considers arrest is necessary for reasons including ensuring appearance in court, preventing further offences, or preserving evidence.
- The arresting officer must inform you of the reason for the arrest at the time of arrest or as soon as reasonably practicable afterwards (CIA, s 137).
- WA does not have a state human rights act, so the requirement to inform a person of arrest grounds relies on statute (the CIA) and common law rather than human rights legislation.
- An arrest without proper grounds or without informing the person may be challenged as unlawful detention. Evidence obtained during an unlawful arrest may be excluded under the Evidence Act 1906 (WA).
Additional Steps in Western Australia
If you believe your arrest was unlawful, contact Legal Aid WA (1300 650 579) or the Aboriginal Legal Service of WA (ALSWA) (1800 019 900). Complaints about police conduct go to the Corruption and Crime Commission (CCC) (ccc.wa.gov.au or 1800 809 000).
Relevant Law: Criminal Investigation Act 2006 (WA), ss 127-139; Criminal Code Act Compilation Act 1913 (WA)
Common Questions
When does right to know grounds of arrest apply?
This right applies whenever an Australian Federal Police officer arrests you for a Commonwealth (federal) offence.It covers offences under federal laws such as the Crimes Act 1914, the Criminal Code Act 1995, drug importation laws, and fraud against the Commonwealth.It applies to all people in Australia, including citizens, permanent residents, and visitors.State and territory police have similar obligations under their own laws, but this right specifically covers federal arrests.
What should I do if the Australian Federal Police arrest me without telling me the reason?
Ask clearly: "Why am I being arrested?" and "What offence am I being arrested for?"Listen carefully to the officer's response and try to remember or write down their exact words.Ask for the officer's name and badge number.Stay calm and cooperate physically while noting any concerns.Ask to speak to a lawyer as soon as possible.
What mistakes should I avoid with right to know grounds of arrest?
Don't physically resist the arrest, even if you believe it is unlawful. You can challenge it later in court.Don't argue or become aggressive — this can lead to additional charges such as obstruction/resisting a Commonwealth official under s 149.1 of the Criminal Code Act 1995 (Cth) (maximum 2 years imprisonment). Note: s 7A of the Crimes Act 1914 does not create a resisting arrest offence.Don't assume you must answer questions just because you have been arrested — you still have the right to silence.Don't sign anything or make a statement before speaking with a lawyer.
Right to Know Grounds of Arrest in other states
Same topic, different jurisdiction. Pick the one that applies to you.