Northern Territory police were kept busy overnight with a string of offences across Darwin and Palmerston.

A 23-year-old man is in custody after robbing a supermarket in Palmerston, a man was bashed by two teenagers when he was walking to his car in Malak, large groups of youths have been roaming the streets of the northern suburbs, a 37-year-old drunk driver crashed into an off-duty police officers car on the Stuart Highway and 30 people were taken into protective custody overnight.

Meanwhile, Crime Stoppers says a new breathalyzer available at supermarkets will help save lives in the Northern Territory.

The disposable breathalyzers are Australian Standard Certified and have the Crime Stoppers logo on it.

The deputy chair of Crime Stoppers NT Dorothy Fox says 17 per cent of the serious injuries caused by car accidents in the Territory are alcohol related.

She's urging people who drink alcohol before driving to get a  Alcohol Tester.

"Drink-driving continues to be an issue in the Northern Territory where nearly half, or 48 per cent, of fatal crashes are alcohol related. Of the people killed, 55 per cent had a blood alcohol concentration equal to or over the legal limit."