Wanganui police will be keeping an eye on cyclists this month and enforcing the wearing of helmets and checking lights and reflectors.
Operation Headcase aims to improve the safety of cyclists, and police say with shorter days and the onset of winter, cyclists become more vulnerable.
Officer in charge of Road Policing Sergeant Colin Wright said there were a number of people who rode bicycles around the city without helmets.
"These riders are putting themselves at risk and can expect to be stopped by police and spoken to about this," he said. "Generally, children are setting the best example by wearing helmets. We need to ensure that adults follow this example."
Lights were required when riding in the dark, and it was highly recommended that cyclists wore bright and reflective clothing.