Wellington City Council is investigating after metal tacks were scattered along Island Bay's cycle path.
This is the third time the tacks have been found on the pavement - it happened once in 2016 and again in 2018.
Wellington father and cyclist Stephen Day told Newshub his family has had four flat tyres in two weeks.
"Once you run over [the tacks] your tyre just goes flat straight away - I don't know what the intention is but it's certainly very annoying."
Day cycles seven kilometres to work in the CBD most days, and he and his family use bikes as their main mode of transport.
He says he hopes whoever is putting the tacks down is just "doing something stupid" and not intentionally malicious.
"I hope it's not just anger at cyclists or taking it out on cyclists."
But city councillor Fleur Fitzsimmons says she suspects whoever is putting the tacks down has ill intent.
"If it had happened once you might think it was an accident but I'm starting to think there's some sabotage intention - so it's a real concern now," she told Newshub.
"Obviously [the tacks] are very dangerous for cyclists especially children so we really don't want to see this."
She says the council has discussed the matter with police.