More than 72 per cent of cyclists who broke the law last year haven't paid their fines, including 4449 people who owe more than $244,695 after being caught by police not wearing a helmet.
But offences by cyclists have dropped by 36.6 per cent since 2013, when there were 14,616 infringements, according to new figures. Police say this is thanks to more people using purpose-built cycleways.
Road policing operations manager Peter McKennie said the cycling infrastructure meant less risk of people being hit by traffic and so "we are less likely to press the enforcement in those environments".
Police have the discretion to charge and assess the risk of the situation. "We always encourage people to adhere to the law by using the appropriate lights on their bikes, wearing reflectorised clothing, having adequate brakes and wearing safety helmets."
Offences labelled "decision unpaid" means the fee is unpaid and referred to the Ministry of Justice.