While today's trampolines appear to be safer than ever, several children jumping inside a safety net trampoline can be as dangerous as cage fighting, a leading paediatrician says.

More than 80 per cent of Australian parents are ignoring basic trampoline safety guidelines, a children's health poll has revealed.

And with one in six children likely to get injured from trampolining, only one in two parents know how the specific first aid for a head injury, dislodged tooth or an unconscious child.

Melbourne Royal Children's Hospital paediatrician Dr Anthea Rhodes said despite changes to the design of trampolines, injuries were on the rise.

"Here at the children's hospital, we've seen over 500 trampoline related injuries in the past 12 months," she said.

"And in the first month following Christmas we see a rise in those injuries at the hospital, some of them can be quite devastating and life changing for the families involved."

Nine-year-old Orla Morrison-Brown was getting off the trampoline in her Kew backyard, when a horrific accident happened.

"She went to step outside of it and just fell, landing on her arm," mother Rachael Brown said. "Straight away I could clearly see it was broken, she was holding it and when she took her hand away there was a lot of blood."

Orla suffered a serious compound fracture in her right arm, which landed her in hospital for three days, with two operations and a cast for five months.

A nurse-in-training, Ms Brown said she was lucky she knew what to do, immediately calming down her daughter, elevating her arm and stopping the blood, while they waited for an ambulance.

She said her daughter still had nightmares about the accident.

"She went back on it for the first time today (Wednesday), but she doesn't want to get back on it, she's having therapy and suffers nightmares," she said.

"All the kids used to go on it, but no one uses it anymore, it affected all of us."

Results from the fifth Australian Child Health Poll, which was directed by Dr Rhodes and surveyed 3,608 children, were released on Wednesday.

The survey found more kids were jumping on trampolines, than riding bikes, scooters or skateboards.

Despite guidelines recommending no more than one child be on a trampoline at a time, more than 80 per cent of parents said they allowed multiple kids.

One in five parents allowed four or more children on a trampoline at once.

"Three quarters of parents have a trampoline with a safety net, and people are more inclined to have more children on a trampoline with a safety net," Dr Rhodes said.

"Allowing multiple children on a trampoline has been compared to cage fighting by our trauma service at The Royal Children's Hospital.

"I'm not suggesting for one minute that we wrap children up in bubble wrap, but what's really important is balancing the risk of getting outside and being safe.

"The other big problem is it if you have children of different ages and sizes, you get double bouncing. We have seen smaller children double bounced and propelled over the safety net of a trampoline."

Her advice? Only one at a time, adequate supervision at all times regardless of age, learn first aid, and make sure you have a first aid kit at home.