Cycling groups in the United Kingdom say any moves to make helmets compulsory would be "detrimental to public health".
Unlike Australia, where helmet use is mandatory, cyclists are free to ride without protection in the UK.
But the British Government is conducting a review of cycle safety, which will include the contentious issue of helmets.
Duncan Dollimore, campaigns director at Cycling UK, said forcing cyclists to wear head protection would discourage people from riding.
"I think it's a move that would be detrimental to public health and the wider population," Mr Dollimore said.
He said the effect of Australia's laws, introduced in the early '90s, resulted in a fewer young people choosing to cycle.
"If you look at the wider population benefits of people being involved in forms of active travel and the benefits of that in terms of reducing congestion … it's just not a wise move," he said.
Australia's yearly cycling participation rate is heading downhill from 40 per cent in 2011, to 34 per cent in 2017, according to the National Cycling Participation Survey.
Mr Dollimore said he believed Australia's helmet laws were part of the problem.
"It's become the activity of the serious cyclist. It's becoming something that you get dressed up to do," he said.
"A word we use over here [is] MAMIL: middle aged man in lycra."
Australians find lack of helmets 'really strange'
In Oxford, which is home to one of the world's most prestigious universities, staff and students regularly ride around without head protection.
Australian student Meredith Caldwell isn't one of them.
"It seems really strange to see so many students around here biking without a helmet," she said.
"It's just bred into [Australians] the need to have helmets and it seems really normal.
"A lot of my student colleagues have had accidents as well, so every day it reinforces that I should be wearing a helmet."
But Oxford resident Mark Wright, who rides without a helmet, said his potential vulnerability made him a safer rider.
"It's a different way of riding," he said.
"Being much sharper, being much more aware and just by riding like that, you're safer."
Doctors call for change
Dr John Black, the medical director of the South Central Ambulance Service, has seen many traumatic injuries caused by bicycle accidents.
He is among those campaigning for compulsory helmets; however, he said they were "not a panacea".
"When I have attended patients with devastating head injuries, many of them have not been helmeted," Dr Black said.
"Many of those accidents have been at low speed and the rest of the injury patterns are entirely survivable."
He said the use of helmets had been proven to save lives.
"All types of head injuries are reduced by 50 per cent if not more," he said.
His claim is backed by research from the University of NSW which found helmet use reduced serious head injuries by 69 per cent.
Dr Black said he had seen real-life proof from his patients.
"They show me their helmet. The helmet might be split in two and those patients are the first to say, my helmet saved my life. And that is very real."
