"Of course we encourage the use of a designated sober driver but accepting rides from strangers could be dangerous.
"Not only that, but picking up passengers for hire is illegal without the correct passenger endorsement."
Larking said getting into a car with someone who has not been vetted carries risks.
"You don't know their background or what their motive is for offering you a ride, so if you get in the car with a person like this you're potentially putting yourself in serious danger," he said.
"If you stick to using registered taxi companies, then you know the driver has been checked out by police, their vehicles are safe and there are other security safeguards in place such as CCTV cameras."
Arranging safe transportation with friends is encouraged, but passengers should always travel with people they know and trust.
"Organise your ride home before heading out for a night, or walk home with a group of friends if the wait time at a taxi stand concerns you," Larking said.
"This is particularly important after a night of drinking, which can make you more vulnerable."
Under New Zealand law a person found operating an unlicensed passenger transport service could face a fine of up to $10,000 for a first offence.
If they are caught more than once the fine leaps to $20,000.
Police ask that anyone who witnesses concerning behaviour such as this contact 111 immediately.
People who have information about these drivers in Dunedin or elsewhere can also share it with Crimestoppers anonymously by calling 0800 555 111.
