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Voluntary Interlocks

While we provide interlocks for the New Zealand Alcohol Interlock Programme, we also offer voluntary interlocks. It’s becoming increasingly common for private and commercial customers to get an interlock installed to ensure their vehicles cannot be driven by anyone who has been drinking.


Feel free to reach out to us if you’re a responsible business owner, safety-conscious individual, or a concerned parent or family member. We’d like the opportunity to discuss potential solutions with you.

Voluntary Interlocks

Voluntary interlocks for commercial or private use are available for lease and they can be programmed to meet your requirements. Unlike the offender interlock programme, voluntary interlocks do not have a monthly servicing requirement meaning they are hassle-free. We require calibration every 12-months to ensure they remain accurate.


Voluntary interlocks are easy to install and can be fitted to all vehicle types, including fuel, hybrid and electric cars. Voluntary interlocks can be applied to various applications to control access to machinery or non-vehicle situations such as cranes, forklifts, tractors, diggers and trains ensuring safety in high risk workplaces.

Where can a voluntary interlock be used?

  • Company vehicle policy
    Drink driving accounts for over 30% of NZs fatal road accidents per year. Installing an interlock in any company vehicles will prevent employees from driving your vehicles whilst impaired. 

  • Dangerous goods or other high risk vehicles
    An accident involving alcohol would spell a disaster for your company. Protect your staff, customers, reputation and business by installing an interlock in high risk vehicles.

  • Young drivers
    Enjoy peace of mind knowing your child will not be able to drink drive. With access to the interlock data, parents can see any alcohol readings giving them the opportunity to help change their child’s behaviour and encourage safer driving habits.

  • Individuals with a drinking problem
    If somebody you love has a drinking problem, it’s possible they could be drink driving. Installing an alcohol interlock is one way you can ensure they are not going to endanger themselves or others on the road.


If you have committed a drink driving offence, you may lose your licence and be disqualified from driving for a specified period of time. After this disqualification period, you will be required by NZTA to get an alcohol interlock licence and get an interlock installed. 

As part of your alcohol interlock program, you cannot legally drive any vehicle without an ignition interlock device fitted. If you own multiple vehicles and wish to drive them, you must have an alcohol interlock fitted to each vehicle.

To complete the program, you must demonstrate the ability to separate drinking and driving over a specified period. However, significant or repeated violations, such as attempting to drink and drive, missed or failed retests or tampering with the alcohol interlock, may lead to extended time on the program and additional penalties.

No certainly not. Smart Start also prodives interlocks for private employers and individuals. Please refer to our Voluntary Interlocks section for more information.

The NZ alcohol interlock programme requires you have an alcohol interlock licence, and an interlock installed, for a minimum of 12 months.

Once you’ve completed 12 months with an interlock installed, you can apply to NZTA to exit the programme. They review your data and get back to you with approval to get your zero alcohol licence.

Once you have your zero alcohol licence you can have your interlock removed from your vehicle.

In most cases, the alcohol interlock programme is a mandatory requirement for individuals to regain a full licence after a period of disqualification from driving. If you choose not to participate, you may face an extended period of disqualification or other penalties.

Please call us on 0800 002 182 if you have any questions about your programme.

The best plan is to have the interlock removed until you are able to afford it. Removal and reinstall charges will apply but if your interlocks remainds installed, the lease costs continue and can end up costing you more than the removal/install. 

Please contact Smart Start for advice if you are having trouble with your programme. We can help advise you what to do to get the best out of your situation.

If the interlock detects alcohol in your breath, it will register a violation and you will not be able to start your vehicle. You will be able to do another breath test after a period of time, but please note that violations could extend your programme.

Always take a retest when requested, even if you are about to turn the vehicle off. Missed retests are considered a violation, and may require you to return to the service centre for an unscheduled service.

If your interlock enters SVCLCK or VIOLOCK you will need a code to be able to start the vehicle. In this case, you will need to pay for a code to enable you to return your vehicle to the service centre. You will need the call code from the head unit to complete your purchase. This can be obtained by pressing #5 on your head unit while the ignition is on. “UNLOCK xxhr” will display and countdown once the code is entered. Ensure you return to the service centre before the countdown ends or else you will be locked out and unable to start your engine.

Alcohol interlocks are fitted with a number of anti-tamper systems. There is a specific technique used to provide a sample, a certain volume of breath is needed, and further samples will be requested at random points in the journey. Tampering with the device will cause recalls and you may incur additional penalties, as tampering is reported to the NZ Transport Agency.

There could be a number of reasons for this. Alcohol is present in a lot of everyday things and interlocks will detect alcohol regardless of where it comes from.

If you have had anything to eat, drink, smoke or chew prior to blowing into your interlock, make sure you wait a few minutes and have a drink of water before you blow into your interlock.

If you think that a mouth contaminant may be the reason for your test failure, wait a few minutes and try again. Your user manual provides you with advice on this.

If you continue to have problems with your interlock device, please call Smart Start on 0800 002 182.

The interlock will stop you starting your car if you try starting your vehicle with alcohol in your system. However, it will never stop your car while the engine is running.

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