Cycling campaigners say they would strongly oppose any move to make helmets compulsory following comments by transport minister Jesse Norman.
Olympic gold medallist Chris Boardman insisted that helmets do not provide a major boost to safety, while charity Cycling UK claimed there was no justification for making their use mandatory.
Speaking at a walking and cycling safety conference on Tuesday, Mr Norman did not rule out the possibility that a forthcoming Government review could make the wearing of helmets and high-visibility jackets compulsory in law.
Cycling groups fear such a policy would reduce the number of people taking to the road and point to research suggesting that vehicles tend to pass closer to bicycles when the user is wearing a helmet.
In comments reported by cycling magazine BikeBiz, the minister responded to a question about compulsory helmets by saying the issue was "something in relation to the Cycle Safety Review where we will see what the evidence and the submissions say".
He went on: "If you want to have a society where a 12-year-old can get on a bicycle it's a serious issue as to whether you're going to mandate hi-vis or helmets, and there will be many arguments about whether the safety benefits outweigh or do not outweigh the deterrent effect that might have on people cycling.
"So we're going to leave that to the review."
The review into cycling safety was announced in September following the conviction of Charlie Alliston, 20, who knocked over and killed pedestrian Kim Briggs as he sped through east London on a bike with no front brakes. He was jailed for 18 months.
Mr Boardman, whose mother Carol was killed in a collision with a pick-up vehicle while cycling in Connah's Quay, North Wales, in July last year, said: "The Cycle Safety Review will be based on evidence, and evidence shows that helmets do not make a significant difference to people's safety.
"We would strongly oppose any moves to make helmets compulsory for cyclists."
Some 102 cyclists were killed on Britain's roads in 2016, up 2% on the previous year.
Sam Jones of Cycling UK said: "There is no justification for making helmet-wearing compulsory. It could undermine levels of cycle use and, in any case, the effectiveness of helmets is not the black and white issue many think it is."
Mr Jones called for cycling safety to be improved by the creation of national design standards to avoid "dangerous cycling lanes being built".
A Department for Transport spokesman said on Friday: "The Government has no plans to mandate the wearing of cycle helmets."