Victoria’s roads authority says sharp metal tacks are being found with increasing regularity along one of Melbourne’s most popular cycling routes, despite efforts by police to track down the culprit.

VicRoads has called on the public for assistance after hundreds of cyclists using the Yarra Boulevard in Kew experienced punctures over the past 16 months.

The first report of tacks being found along the 13km track, affectionately known among cyclists as “the Boulie”, was in February last year. VicRoads regional director for metro south-east, Aidan McGann, said attacks had continued since then, with the bits of metal now being found about twice a month.

“There has been a really strong response from the community to put a stop to this issue and we encourage any suspicious behaviour to be reported to Victoria police,” McGann said.

“VicRoads will continue to sweep the boulevard with a purpose-built magnet

and support the cycling community. The Yarra Boulevard is wide enough for vehicles and cyclists to share the road together safely, so it is disappointing that this is an ongoing issue.”

The most recent attack occurred last Tuesday, he said.

Pulled this out of my tyre today on Yarra boulevard, no spares so had to call friend for a ride home #boulietacks pic.twitter.com/jR29mTJc52 — Andrew Jones (@andrewjones141) June 21, 2015

Bicycle Network Victoria spokesman Gary Brennan said it was unclear who was behind the attacks. Riders had been “exceptionally lucky” so far, he said, and had suffered no serious accidents or injuries that he was aware of.

But there had been reports of serious punctures that led to people coming off their bikes, Brennan said. A Twitter hashtag, #Boulietacks, had emerged in response, he said.

“The Boulevard traverses parkland area where it is very difficult to detect the offender, and there is a limit to the resources that the police and other authorities can commit to this,” Brennan said.

“We’re lucky there hasn’t been a serious incident, but it remains an extremely risky situation for riders. But we don’t want riders to be deterred, we think the best thing to do is to keep riding in order to show the world we will not be intimidated.”

Brennan said he was confident police were doing everything they could. But some cyclists had taken matters into their own hands, he said, installing cameras on their bicycles and in cars parked near the route at night. The network estimates cleaning up the attacks has cost at least $70,000.

Last month, hundreds of riders took part in a 24-hour cycle to protest against the persistent littering of the road with tacks.

The City of Boroondara council has installed three repair stations along the route to deal with the frequent punctures.

Victoria police said it was continuing to investigate.