Police in Christchurch expected an influx of boyracers into the city on Saturday night, before a cruising ban takes effect on Thursday.
The ban covers some suburban streets and all multi-lane streets, including the four avenues where boyracers gather.
Inspector Al Stewart says there has been a lot of discussion on social networking sites indicating that boy racers may be planning an event.
He says there would be a high level of police enforcement on the streets.
From 1 July, people who breach the cruising bylaw could be fined up to $1000 or charged an infringement fee of $150.