The chairperson of Bike Auckland says bike theft is rampant in the region and people need to secure them with quality locks.
Barbara Cuthbert said the theft was often organised crime involving an outlet for bikes and the least-secured ones tend to be stolen.
She said CCTV footage showed some owners used light cable locks, which could be broken simply by pulling, and others used cafe locks, which only lock the wheel.
Sometimes thieves used loppers or bolt cutters to cut the lock, Cuthbert said.
"We've seen a whole range of them picked up on CCTV and the common theme is bikes that aren't heavily locked and by heavily, I mean something like a D-lock ... because you've actually got to saw through it.
"Those bikes are more valuable than they used to be because increasingly they're e-bikes, so they really are a very attractive target for organised theft, which is what we've seen."
Cuthbert said there had been a 16 percent increase of people biking over the last three years, and the escalated demand for bikes had been driving the theft.
"The cost of e-bikes is a barrier - is off-putting for people, so presumably if they can buy one online for cheaper they will do so," she said.
She said it was timely for them to do another campaign to combat bike theft.
In a statement, police said they were not immediately aware of an overall increase in bike thefts across Auckland, but they were aware anecdotally of a small increase in reports of bike thefts in the Auckland City central area recently.
"Police find in many cases would-be offenders are opportunistic in terms of targeting their victims.
"That's why it's important to not give offenders any opportunities. Take a few steps to secure your items, which could help you prevent becoming victims of theft or burglary."
They encourage people to lock up their bike with a good quality chain whenever they're not using it.