A survey has revealed most parents are ignoring trampoline safety guidelines and one in two don't know how to properly treat head injuries.

Trauma specialists say it's simply not safe for kids to jump on a trampoline together, as a new report suggests parents are thumbing their noses at safety guidelines.

Trampolining is now more popular than riding a bicycle, a Royal Children's Hospital Melbourne survey suggests, but only a third of all children are always supervised by an adult.

Even when it comes to infants and toddlers under the age of two, some 20 per cent aren't always watched by a parent.

Australia's consumer watchdog advises one child uses a trampoline at a time and that child - regardless of age - be supervised.

But the hospital's survey of 2000 parents, released on Wednesday, suggests 81 per cent of them allow more than one child to jump at a time.

Half of all parents don't know how to administer first aid to a child with a head injury, broken or dislodged tooth or who is unconscious.

Pediatrician Anthea Rhodes says trampolines can be fun and safe when used properly.

"But allowing multiple children on a trampoline has been compared to cage fighting by our trauma service at the Royal Children's Hospital," she said in a statement.

Oz Trampolines founder Richard Haby says the introduction of padding and netting has been a huge improvement for safety in the past decade.

But their widespread use may have made parents think it's okay to put multiple kids on at a time, he told AAP on Wednesday.

Every trampoline purchased from Mr Haby's company includes a copy of the ACCC guidelines but he'd like to see regulated standards for trampoline parts.

"I'm sure you've seen trampolines with the nets all broken or half hanging down," he said.

"At the end of the day, two kids are going to be on a trampoline, and there will be head clashes, just like kids are going to fall off a bike.

"But if we could make the trampolines of better quality ... that could be a different way to reduce the accident rate."