Updated June 16, 2026
A positive roadside drug test in Victoria can feel like the end of the matter, but it is not. The roadside device only gives a preliminary reading. A charge depends on a confirmed laboratory result, and police must follow strict steps along the way. If any of those steps go wrong, you may have grounds to challenge the case. This article explains how testing works under the Road Safety Act 1986 (Vic), what happens after a positive result, and the legal options open to you.
Victoria conducts random roadside drug testing under Part 5 of the Road Safety Act 1986. The laws on driving under the influence of drugs are set out in that Act. The law targets the presence of certain drugs, not impairment. Driving with any level of a prescribed drug in your blood or oral fluid is treated separately from driving while impaired. That means you can be charged even if you felt fine to drive and took the drug days earlier.
The first test at the roadside is a preliminary oral fluid test that checks a saliva sample for the three prescribed illicit drugs. A positive reading here is not proof on its own. If the screen is positive, the officer moves on to a second oral fluid test to confirm the preliminary result.
If the preliminary test is positive, police take a second oral fluid sample (a blood test is usually required in cases of drink driving and a crash). That sample is sent to the Victorian Institute of Forensic Medicine, a government laboratory, for confirmation, and the decision to charge or stop the matter is based on this result. A confirmed positive laboratory test will result in a drug driving charge.
Drug testing in Victoria works in two stages. Here is a clear breakdown of the process.
Roadside testing uses saliva collected on a small device. Oral fluid tests detect only the presence of the listed drugs, and they are not an impairment test. Some drivers take over an hour to produce enough oral fluid for the second sample.
The roadside test screens for three prescribed illicit drugs. These are methylamphetamine (also called speed or ice), MDMA (ecstasy) and THC, the psychoactive part of cannabis. Some drugs can be detected in your saliva days after you took them, even if you feel fine to drive, with detection time varying by drug, amount, and how often it is used.
The process after a positive roadside test looks like this.
After a positive preliminary test, you must provide the second oral fluid sample. This is the sample sent for laboratory analysis, and the laboratory result decides whether you are charged.
Victoria Police can issue an on-the-spot banning notice that stops an alleged offender from driving for 12 or 24 hours. Once the laboratory confirms the result, you will either get an infringement notice (a fine) or a summons to attend the Magistrates’ Court.
Police have the power to immediately suspend your driver’s licence if they charge you with certain drug driving offences, and that suspension lasts until the charges are decided in court. There is no hardship licence for drug driving in Victoria, so there is no special permit allowing you to drive for work or family reasons.
A positive test can be challenged, and cases often turn on whether the correct process was followed.
The Act and regulations set out how each test must be carried out. If the device was not used correctly, or a required step was skipped, the result may be open to challenge.
The second sample must be collected, stored and sent to the laboratory correctly. Gaps in how the sample was handled can raise doubt on the reliability of the result.
Police can only require a test in set circumstances. An officer may require a preliminary oral fluid test if they have reasonable grounds to believe the person drove or was in charge of a vehicle within the previous three hours. If the request was not lawful, the evidence that followed may be questioned.
The prosecution must prove you were the driver and that the sample was taken within the time allowed. The drug must have been present at the time of driving. Questions about who was driving or when the sample was taken can be a real issue.
Driving after consuming cannabis or other over-the-counter drugs adds another layer to the process. Here is how those cases are treated.
From 1 March 2025, magistrates can decide whether or not to cancel the licence of a person who tests positive for THC and is using prescribed medical cannabis. This is court discretion, not an automatic defence. It remains illegal to drive with any amount of THC in your system; the outcome is at the court’s discretion, and fines may still apply. To ask for this discretion, you generally need your matter heard in court rather than paying an infringement. A closed-circuit track trial commissioned by the Victorian Government is studying the effects of prescribed THC on driving, with outcomes expected in 2026.
The three roadside drugs are illicit drugs. For prescription or over-the-counter medicine, the offence is driving while impaired. If police believe a driver is impaired by another drug or medication that is not picked up by the roadside test, they may ask for a drug impairment assessment of coordination and cognitive function. If you plead not guilty, your defence will need to show that you took the medicine exactly as directed by your doctor, chemist or dentist.
Drug driving penalties can range from licence cancellation to convictions, depending on your case. Let’s take a closer look at the possible outcomes.
For a first offence, your licence will be suspended or cancelled for at least six months. For a first offence only, cancellation may be avoided if you complete a Behaviour Change Program within three months of the suspension taking effect.
First-time offenders are usually fined rather than jailed. Where the matter is dealt with by infringement notice, the fine is significantly lower than where the matter proceeds to court. The value of a penalty unit is set by the Victorian Government each financial year.Whether a presence offence results in a criminal conviction depends on how the matter is dealt with. If an infringement notice is paid without objection, a conviction is recorded. Where the matter proceeds to court, the magistrate has discretion whether to record a conviction. All findings of guilt appear on the police database regardless of whether a conviction is formally recorded.
| Factor | Drug driving laws for first offence | Second or later criminal record (within 10 years) |
| Minimum licence loss | At least 6 months | At least 12 months |
| Usual outcome | Fine or court summons | More likely court, higher fines |
| Behaviour Change Program | Required | Required |
| Hardship or work licence | Not available | Not available |
A subsequent offence carries a longer disqualification of not less than 12 months. Repeat offences also tend to bring higher fines and a greater chance of a court conviction.
Many people are shocked right after the event. That’s normal. However, here is what an individual should do immediately after the charge to ensure the best possible outcome.
Write down what happened as soon as you can. Note the time you were stopped, the time of each test, what the police said, and how the samples were handled. These details matter if you later challenge the charge.
Speak to a lawyer before you pay an infringement or plead guilty. Paying a fine can result in a licence suspension and close off options, including the medicinal cannabis discretion.
Yes. A roadside result is only preliminary. A charge depends on a confirmed laboratory test, and you can challenge how the test was done, how the sample was handled, or whether the police request was lawful.
No. The roadside reading lets police take a second sample. A charge follows only after the laboratory confirms the result.
Refusing is itself an offence. Under section 49(1)(eb) of the Road Safety Act 1986, refusing to provide a saliva sample can lead to fines and loss of licence, with harsher penalties for repeat offenders. The consequences can be heavier than for the drug driving charge.
Not fully. Since 1 March 2025, a magistrate can choose not to cancel your licence if you hold a valid prescription and were not impaired, but driving with THC present is still illegal, and fines may apply.
Often yes, especially if you want to contest the charge or ask the court to use its discretion. Get legal advice from drug driving lawyers before deciding.
“This content is for informational purposes only and should not be considered legal advice. Please consult a qualified criminal defence lawyer before making any decisions regarding your matter”
