Wellington City Council is on the hunt for whoever is scattering tacks along the Island Bay cycleway.
Council spokesperson Victoria Barton-Chapple said they had dealt with this issue back in 2016 and 2018, and had hoped that would be the last of it.
"Our street cleaners do regular sweeps, but it's happening again and we're not putting up with it anymore."
She said they would be reporting any CCTV footage they could find to police.
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"This behaviour is unacceptable and needs to stop before someone gets seriously injured."
The tacks were noticed by a member of Island Bay Healthy Streets, who warned residents on Twitter.
They said there appeared to be tyre punctures on both sides of The Parade this morning.
Cycling Action Network spokesman Patrick Morgan said he wasn't sure what the motive was, but this kind of sabotage wouldn't work.
"Cyclists are harder than nails. The point of a cycleway is to make biking more convenient and attractive. And you can't stop progress with a few nails."
When the tacks started reappearing in 2018, Cycling Action Network auctioned off a plaque of tacks to raise money for cycling advocacy.