The warning follows a dramatic rise in the number of patients admitted to the Royal Belfast Hospital for Sick Children with serious head injuries.

UTV spoke to the parents of one 11-year-old girl who was admitted to intensive care when she came off her bike last week.

She was not wearing a helmet and needed three hours of neurosurgery to save her.

"She's really suffering in pain, crying out every two seconds and she's got stitches everywhere," her mum told UTV.

Neurosurgeon Roy McConell said it was an all too familiar story.

"In the last ten days, we've had six children with very serious head injuries all having been admitted," he said.

"All were on bikes and none wearing helmets. The parents had bought helmets, but the children had opted not to wear them. I think largely because it's not cool.

"In the last week, we've had three children admitted to the intensive care unit - we've had neurosurgery on three so far and we're removing brain haematomas.

"We're measuring the pressure in their heads and treating them with drugs to treat the pressure in their heads. We're also seeing a lot of skull fractures."

The first stage of a private members bill to make wearing cycle helmets compulsory will be heard in Stormont in September - it is hoped it will become law within the next six months.

Parents could then face a £50 penalty if their children do not wear safety headgear.

But payments for not wearing them would be suspended if it is a first offence and the person later purchases the protective equipment.

A spokesman for brain injury charity Headway said: "There are still children being injured in cycling accidents so more needs to be done through both education and legislation."

Helmet wearing rates across the UK have increased steadily since 1994 with up to a third wearing them on major roads.

The charity's spokesman added: "Alongside the evidence that cycle helmets save lives and prevent lifelong disability is the common sense notion that wearing a helmet surely provides one's fragile skull with more protection than not wearing one.

"Too many Headway service users sustained their brain injuries as a result of cycling accidents.

"While some spend their days regretting not wearing a helmet, others have been told by the doctors treating them that had they not been wearing one, they would not have survived.

"We all think 'it will never happen to me'. Unfortunately, the evidence proves it does happen and cyclists need to accept they are at risk and better protect themselves before it's too late."

SDLP Assembly member Pat Ramsey has finished the first draft of a Stormont bill to be submitted next month.

He said he hoped the bill would receive the full support of his Assembly colleagues.

"It is clear and obvious from brain injury group Headway that there is an increasing number of young people having serious accidents on their bikes," he said.

"We must legislate for this at the Assembly. Particularly when some accidents sustained by young people can easily ruin their lives permanently."

A Department of Environment spokeswoman said: "The department's current policy mirrors the Department for Transport's in Great Britain and encourages all cyclists to wear approved helmets.

"There is currently no legal requirement for cyclists in Northern Ireland to wear helmets on public roads.

"Any cycle helmet used should meet current regulations and be of the correct size and safely secured. These guidelines, along with further advice on appropriate clothing for cycling, are included in the Highway Code."