An Interlock Order is a court-ordered requirement that a driver install and use an alcohol interlock device in their vehicle after a drink driving offence. These devices prevent the car from starting unless the driver provides a zero-alcohol breath sample.
Interlock orders are now mandatory across most Australian states and territories for certain PCA (Prescribed Concentration of Alcohol), DUI, or refusal offences — particularly mid-range, high-range, repeat, or aggravated drink driving offences.
If you’re facing a drink driving charge, it’s critical to understand whether an interlock order applies, how long it lasts, and what the costs and consequences are.
An alcohol interlock is an in-car breath testing unit connected to the ignition system. It requires the driver to blow into the device before the vehicle can start. If alcohol is detected, the car will not start.
The device:
Records breath test results
Requires random retests during the drive
Logs any tampering attempts
Must be regularly serviced and monitored
A court may impose an interlock order if:
You are convicted of mid or high-range PCA
You refuse a breath or blood test
You have multiple drink driving offences in 5 or 10 years
Your BAC was 0.08 or higher (in some states)
You are under a mandatory interlock scheme
Some states allow first-time low-range PCA offenders to avoid court but still face a mandatory interlock licence suspension.
After your disqualification period ends, you may:
Be granted a restricted interlock licence
Only be allowed to drive vehicles fitted with the device
Be required to pay for all installation, servicing, and monitoring costs
Face a minimum 6- to 48-month interlock period, depending on the offence and state
Failure to comply can lead to extended interlock periods, licence cancellation, and criminal charges.
Some jurisdictions allow exemption applications in rare cases, such as:
Medical inability to use the device
No access to a vehicle
Financial hardship, in limited cases
However, exemptions are very limited, and most courts will not waive interlock orders, even for hardship.
New South Wales (NSW)
Under the Road Transport Act 2013 (NSW), interlock orders are mandatory for mid and high-range PCA, repeat offenders, and refusal offences. Minimum interlock period is 12 months. If you fail to enter the interlock program, your licence remains suspended indefinitely.
Victoria (VIC)
Under the Road Safety Act 1986 (VIC), interlocks are mandatory for all drink driving offences with a BAC of 0.05 or above. The minimum period ranges from 6 months to 4 years, depending on the offence. Interlocks are also required for drug driving and combined offences.
Queensland (QLD)
Under the Transport Operations (Road Use Management) Act 1995, interlocks are mandatory for high-range drink driving, repeat offences, and refusal offences. Minimum interlock period is 12 months, and non-compliance leads to extended disqualification.
Western Australia (WA)
WA operates a mandatory interlock scheme for high-risk drink drivers, including those with a BAC of 0.15 or above or repeat offences. Interlock period is at least 6 months, and compliance is strictly monitored.
South Australia (SA)
Under the Motor Vehicles Act 1959 (SA), interlocks apply for BAC of 0.08 or more, refusal offences, or repeat drink driving. Periods range from 12 to 36 months, and costs must be fully paid by the driver.
Australian Capital Territory (ACT)
Under the Road Transport (Alcohol and Drugs) Act 1977, interlocks are mandatory for serious drink driving offences or where disqualification exceeds 3 months. Interlock period is 12 months or more.
While we don’t provide legal advice—as every case is unique and only a qualified lawyer is permitted to do so—we’ll do our best to guide you with relevant general information. If we’re unable to assist, we can refer your query to a licensed criminal lawyer.
