Can You Refuse a Random Breath Test in NSW?
- Michael Confos
- Jul 19
- 7 min read
The short answer is no.
In New South Wales, police have broad statutory powers to conduct Random Breath Testing (RBT) to detect drink driving offences. If a police officer lawfully requires you to submit to a roadside breath test, refusing to comply is itself a criminal offence.
Many drivers mistakenly believe they can simply decline the test because they have not committed another offence or because they believe police have no reason to stop them. That is incorrect.
Unlike many other police investigations, Random Breath Testing does not require police to suspect that you have been drinking before requiring a breath test.
Understanding how Random Breath Testing works can help you avoid making a mistake that may result in serious penalties.
If you have been charged after refusing a roadside breath test, you should obtain legal advice as soon as possible.
For a complete guide to drink driving offences in NSW, visit our Drink Driving Lawyer Sydney page.
What Is a Random Breath Test?
A Random Breath Test (RBT) is a roadside screening procedure that allows police to check whether a driver has alcohol in their system.
The purpose of Random Breath Testing is to improve road safety by detecting drink drivers before accidents occur.
Police conduct millions of Random Breath Tests across New South Wales every year.
Unlike many other police powers, officers do not need to suspect that you have consumed alcohol before requiring you to undergo a roadside breath test.
Why Is It Called “Random”?
The word random often causes confusion.
It does not mean police randomly choose whether they can stop drivers.
Rather, it means police may stop drivers without needing any prior suspicion that an offence has occurred.
For example, police may conduct:
roadside testing stations;
mobile RBT operations;
holiday enforcement campaigns;
highway testing operations;
local traffic operations; and
individual roadside stops.
In each of these situations, police can lawfully require a breath test even if you have driven perfectly.
Lawyer Insight
One of the most common misconceptions is that police need a reason to stop you for an RBT.
They do not.
The legislation specifically allows police to require Random Breath Tests without first suspecting that a driver has consumed alcohol.
What Happens If You Say No?
If you refuse a lawful Random Breath Test, you may commit a criminal offence.
Importantly, refusing a roadside breath test is often treated very seriously because it undermines the effectiveness of drink driving enforcement.
Many people incorrectly believe refusing the test will prevent police from proving they were over the legal alcohol limit.
In reality, refusing can expose you to significant penalties in its own right.
Our article What Happens if You Refuse a Breath Test in NSW? explains these offences in greater detail.
Can You Refuse Because You Haven’t Been Drinking?
No.
Whether you believe you are under the legal limit is irrelevant.
If police are lawfully exercising their powers, you are generally required to comply with the breath test.
Even drivers who have consumed no alcohol at all must comply with a lawful requirement.
Can Police Physically Force You to Blow?
Police cannot physically force air out of your lungs into a roadside breath testing device.
However, deliberately failing to provide a sufficient sample or pretending to comply may still amount to an offence.
Simply going through the motions without genuinely attempting to provide a breath sample is unlikely to avoid liability.
We discuss this further in Can Police Force You to Take a Breath Test in NSW?.
What If You Have a Medical Condition?
Some people genuinely struggle to provide a sufficient breath sample because of a medical condition.
Examples may include certain respiratory illnesses or physical limitations.
Whether a medical condition provides a lawful excuse depends on the particular circumstances and the available medical evidence.
Simply telling police you have asthma or another medical condition will not automatically excuse non-compliance.
Practical Example
A driver is stopped at a Random Breath Testing station after leaving work.
The driver says:
“I haven’t had a drink all day, so I’m not doing the test.”
Even though the driver genuinely believes they have consumed no alcohol, police may still lawfully require the roadside breath test.
Refusing because you think you are innocent may still result in criminal charges.
Relevant Legislation
Police powers to conduct Random Breath Testing are primarily contained in the Road Transport Act 2013 (NSW).
The Act authorises police to stop drivers and require roadside breath testing without first establishing reasonable suspicion that alcohol has been consumed.
The legislation also creates offences for refusing lawful requirements relating to breath testing and breath analysis.
You may also find these articles helpful:
Can Police Enter Your Home to Conduct a Breath Test in NSW?
Can You Accidentally Refuse a Random Breath Test?
Yes, it is possible.
Not every refusal involves someone deliberately saying “no.”
In some cases, drivers unintentionally place themselves at risk of being charged because they misunderstand the police officer’s instructions or fail to provide an adequate breath sample.
For example, issues can arise where a person:
repeatedly stops blowing too early;
deliberately pretends to blow into the device;
argues with police instead of following instructions;
walks away before testing is completed; or
refuses to accompany police for a breath analysis after returning a positive roadside test.
Whether an offence has been committed depends on the facts and whether the prosecution can prove that you failed to comply with a lawful requirement.
Lawyer Insight
Not every refusal case is straightforward.
Sometimes the real issue is whether the driver genuinely attempted to comply or whether police correctly explained the testing procedure.
These factual disputes can become important in court.
What Happens If You Return a Positive Roadside Breath Test?
A roadside Random Breath Test is only a screening test.
If it indicates the presence of alcohol, police will usually require you to undergo a breath analysis using a more sophisticated instrument.
The breath analysis—not the roadside screening device—is generally relied upon as evidence of your prescribed concentration of alcohol.
Refusing to accompany police or refusing the breath analysis may itself amount to a criminal offence.
What Are the Penalties for Refusing a Random Breath Test?
The penalties depend on the particular offence and the circumstances of the case.
A conviction may result in:
substantial fines;
a period of licence disqualification;
a criminal conviction;
participation in the Mandatory Alcohol Interlock Program in appropriate cases; and
other consequences prescribed by law.
Because the consequences can be significant, obtaining legal advice at an early stage is important.
For more information, read our guide to Drink Driving Penalties in NSW.
Are There Any Defences?
Potentially.
Every refusal case should be carefully examined.
Depending on the circumstances, issues may arise concerning:
whether the police requirement was lawful;
whether the driver understood the instructions;
whether a genuine medical condition prevented compliance;
whether sufficient opportunity was given to provide a sample;
whether police followed the correct statutory procedures; and
whether the prosecution can prove the offence beyond reasonable doubt.
The availability of a defence depends entirely on the facts of the individual case.
Relevant Legislation
The principal legislation governing Random Breath Testing is the Road Transport Act 2013 (NSW).
Among other things, the Act:
authorises Random Breath Testing;
permits police to require breath analysis;
creates offences for refusing lawful testing requirements; and
establishes the penalties applicable to those offences.
Relevant NSW Case Law
Cases involving alleged refusals frequently depend on the particular facts.
The courts generally consider issues such as:
whether the police requirement was lawful;
whether the driver intentionally failed to comply;
whether any medical condition genuinely prevented compliance; and
whether the prosecution has proved the offence beyond reasonable doubt.
Because these matters are highly fact-specific, legal advice should be obtained before deciding whether to plead guilty or defend the charge.
Frequently Asked Questions
Can I refuse an RBT because I know I’m under the legal limit?
No. If police are lawfully exercising their powers, you must comply regardless of whether you believe you have consumed alcohol.
What if I accidentally don’t blow hard enough?
That depends on the circumstances. A genuine inability to provide a sufficient sample is different from deliberately failing to comply. The facts of each case will determine whether an offence has been committed.
Can I refuse because I have asthma?
Not automatically. A medical condition does not necessarily excuse non-compliance. Whether it provides a lawful excuse depends on the evidence and the circumstances.
Can I ask to speak with a lawyer before taking the test?
Police may lawfully require immediate compliance with breath testing requirements. Delaying or refusing because you want legal advice may still expose you to criminal liability.
Why Choose Michael Confos?
Refusal offences are often more complicated than drivers realise. Whether police lawfully exercised their powers, whether the testing procedure was properly followed and whether a genuine defence exists can all significantly affect the outcome of your case.
If you have been charged with refusing a Random Breath Test, obtaining legal advice early may help you understand your options and protect your licence.
You may also find these articles helpful:
Michael Confos is a criminal lawyer in Sydney. Contact today for a free consultation.
Disclaimer
This article is intended to provide general information only and does not constitute legal advice. The information is general in nature and may not apply to your particular circumstances. Every legal matter is different, and the outcome of any case will depend on its specific facts and the applicable law.
You must obtain your own legal advice from a qualified legal practitioner before acting or relying on any information contained in this article.
Reading this article does not create a solicitor-client relationship with Michael Confos.
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