Police in Christchurch have received a number of complaints about a new craze involving adult-sized trikes being ridden downhill at speed.
They say drift-triking is occuring mostly at night and often on the wrong side of the road.
Senior Sergent Glenn Nalder says hill-residents in the suburb of Huntsbury, near the Port Hills, are not happy about the racing because it's reckless and noisy.
He says drift-triking also puts motorists at risk.