"Basically the driver has to blow into the device and pass the test before they can start their car," Wills said.
"Then they get random requests every so often to stop and blow into it again to confirm that they're still all good."
A judge can only order a defendant to get an alcohol interlock if they have a New Zealand driver's licence and if they have regular access to a vehicle.
Then, after a period of suspension from driving, the defendant can arrange to have the device installed which they will be required to lease for 12 months.
This means they will be able to apply for an alcohol interlock licence, allowing them to continue driving to work and running errands.
"We've been an installer of the devices for three months now, we've only done one installation so far, but we're actually doing another one today," Wills said.
"Now that the courts are enforcing it, we're just sort of seeing people coming through now."
AMT installs devices from Smart Start Interlocks NZ based in Northland at a cost of $358, unless the driver has a subsidy which reduces the cost to $138.
The driver then leases the device from Smart Start at a rate of $183 a month or $133 if they have a community services card.
"Each month they've got to come and get it serviced and each month we download all of the information out of the unit," Wills said. "If they've tried to start it after they've been drinking, it won't let them and all that information goes to the LTSA (Land Transport Safety Authority)."
A service costs $183 or is $30 cheaper with the subsidy and can only be done where the devices are installed.
After driving with the device for 12 months with no violations, the driver can then apply for a zero alcohol licence and have the device removed, again for a fee.
"Most people that have got the Smart Start have said it's a good thing, someone just had it removed, she finished her time and said 'I'm not going to do this again'," Wills said. "It's not a cheap exercise for them."
When a driver receives the zero alcohol licence, it means they cannot have any alcohol in their system when they drive, otherwise they will be convicted.
They must hold the licence for three years before they can apply to get a standard licence back.