Western Australia, Australia

Police drug search powers in Western Australia: stops, warrants, sniffer dogs and border search areas

Most drug charges in Western Australia begin with a search: of a person on the street, a car at the roadside, a house under warrant, or a bag at an airport.

Published 27 October 2026

Knowing what powers police have, and the conditions attached to them, helps explain how a case started and whether there may be questions about how the evidence was obtained.

The main powers are found in the Misuse of Drugs Act 1981 (WA), which works alongside the general powers in the Criminal Investigation Act 2006 (WA). This article focuses on the drug-specific powers.

Searching without a warrant: section 23

The most frequently used power is in section 23 of the Misuse of Drugs Act. If there are reasonable grounds to suspect that a person has in their possession any thing:

• in respect of which an offence has been, is suspected to have been, or may be committed;
• that has been, or may be, used to commit an offence; or
• that may provide evidence of an offence,

a police officer may stop and detain the person and search them, together with any baggage, package, vehicle or other thing in their possession. Police may also stop and detain a vehicle for that purpose, using such force as is reasonably necessary.

What “reasonable grounds to suspect” means

Reasonable suspicion is a lower standard than reasonable belief. It does not require proof, but it does require more than a hunch, a guess or idle curiosity. There must be facts that would lead a reasonable person to suspect that the person has something connected to an offence.

The grounds have to exist before the search begins. Something found during a search cannot be used to justify the decision to start it. Whether reasonable grounds existed is a common point of dispute when the lawfulness of a search is challenged.

Rules about personal searches

Section 23(2) requires that a person searched under this power be searched only by a person of the same sex or by a medical practitioner. If that is not practicable at the scene, police may detain the person, or take them somewhere it is practicable, but only for as long as reasonably necessary.

Search warrants: section 24

For premises, vehicles and places, police often apply for a search warrant under section 24. A justice of the peace may grant a warrant if satisfied, on information given on oath, that there are reasonable grounds to suspect that a relevant thing may be in or on the vehicle, premises or place.

A warrant under section 24:

• authorises police to enter and search the named vehicle, premises or place at any time or times within 30 days;
• allows police to search any person found there, along with any baggage, package or other thing; and
• permits the use of reasonably necessary force and assistance.

The same-sex search rule applies to people searched under a warrant.

A warrant is only as good as the information behind it and the limits written into it. Questions can arise about whether the information sworn was accurate, whether the warrant was properly issued, and whether police stayed within its terms.

Powers that come with a search: section 25

When police exercise their section 23 power or a warrant, section 25 allows them to seize or copy documents, and to require a person to give information that is within their power to give. Failing to comply without reasonable excuse, or giving information known to be false or misleading, is an offence.

Importantly, section 25(3) provides that a person cannot refuse to comply only because the answer might incriminate them, but information given under that requirement is not admissible against them in proceedings for any offence other than giving false or misleading information. This is a narrow protection and the interaction between this requirement and the general right to silence can be complex, so legal advice is important.

Hindering police: section 29

Wilfully delaying or obstructing police exercising these powers, or concealing items police are entitled to find, is a separate simple offence under section 29. Disputing the lawfulness of a search is usually best done later, through a lawyer, rather than physically at the scene.

Drug detection dogs and devices

The Act defines a preliminary drug detection test as leading or placing a drug detection dog near a person or property, or using an approved electronic drug detection device. A positive indication from a dog or device can, in the specific circumstances set out below, itself provide the reasonable grounds needed for a full search under section 23.

Drug detection areas: Part 4A

Part 4A of the Act allows targeted searches without individual suspicion in defined circumstances.

A senior police officer (superintendent or above) may issue a vehicle search authorisation if satisfied there are reasonable grounds to suspect an area is being, or is likely to be, used to transport prohibited drugs, plants or controlled precursors. The authorisation:

• must define a drug detection area that is not in the Perth metropolitan region and is no larger than 5 square kilometres;
• lasts for no more than 14 days, though it can be renewed; and
• cannot take effect if three such authorisations are already in force.

Within the area, police may stop vehicles, search them, detain them for a reasonable period, require occupants to open compartments or stay in the vehicle, and carry out preliminary drug detection tests on drivers and passengers. A positive test is treated as giving reasonable grounds to suspect for a section 23 search.

Part 4A also allows authorisations for delivery business premises, for periods of up to 24 hours, so that consigned parcels can be screened and opened if a test detects drugs. Australia Post is excluded from this definition.

Border Search Areas: Part 4B

Since 2023, Part 4B has created Border Search Areas (BSAs). These are fixed areas listed in Schedule 6A, including Perth Airport, Fremantle Port, several regional ports and airports, and road crossings at the WA/SA and WA/NT borders such as the Eyre Highway at Eucla.

Police authorised by an officer of inspector rank or above (ratified by a superintendent within 24 hours if issued by an inspector) can, for up to 28 days per authorisation:

• conduct preliminary drug detection tests on people in a public place within a BSA, detaining them for a reasonable period to do so; and
• stop, search and detain vehicles in the BSA.

The powers cannot be used on people participating in industrial action, a political protest, a religious or cultural activity, an educational activity, or seeking or providing medical or emergency services. The Corruption and Crime Commission has oversight and reporting functions over the use of these powers.

Undercover operations

Not all drug evidence is gathered through searches. Some cases arise from undercover officers buying drugs or arranging transactions. These operations are governed by a separate statutory scheme under the Criminal Investigation (Covert Powers) Act 2012 (WA), and they raise distinct questions about whether police induced the offence. Our article on entrapment and undercover drug operations in Western Australia explains how that framework operates and why police involvement in a transaction does not, by itself, create a defence.

What if a search was unlawful?

An unlawful search does not automatically make the evidence inadmissible. In WA, courts have a discretion to exclude unlawfully or improperly obtained evidence, weighing the public interest in convicting offenders against the public interest in discouraging unlawful police conduct. Factors include whether the breach was deliberate or reckless, how easily police could have complied with the law, and the seriousness of the offence. That balancing exercise is explained in our article on the Bunning v Cross discretion.

Practical points

If you are stopped or searched by police in WA:

1. Stay calm and do not physically resist. Obstruction is a separate offence, and the lawfulness of the search can be tested later.
2. Note the details. The time, place, officers involved, what was said and what reason, if any, was given for the search can all become important.
3. Be careful about volunteering information. Beyond what the law requires, what you say can be used as evidence.
4. Seek legal advice promptly. A lawyer practising criminal law in Western Australia can examine whether police had the power they relied on and whether they stayed within it. Quantity-based supply charges are covered in our guide to possession with intent to supply.

For information about legal services in Perth, visit our Perth team at Podmore Legal — Perth criminal defence specialists in drug offence matters.

Related reading: entrapment and undercover drug operations, possession with intent to supply, excluding unlawfully obtained evidence, police drug search powers, the Virginia criminal law overview, and the TroofLaw blog.