Tampere, Finland: The largest review yet of bike helmet use by 64,000 injured cyclists worldwide has found helmets reduce the chances of a serious head injury by nearly 70 per cent.

Claims that bike helmets damaged the neck and caused serious brain injury (diffuse axonal injury) were also found to be wrong in the study by University of NSW statistician Dr Jake Olivier who presented on Tuesday to the international injury prevention conference Safety 2016 in Finland.

Advocates of mandatory helmet laws – which only exist in a small number of jurisdictions including Australia and New Zealand – hope the Australian research will debunk "junk science" often cited by helmet opponents in the ongoing and heated debate.

Even at Safety2016, the leading injury prevention conference worldwide, a Helsinki emergency room doctor raised some questions about the efficacy of helmets, saying it was "not so easy to show". Another local expert disagreed: of Finland's 29 cycling fatalities in 2014, about eight people would have been saved if they'd worn a helmet.