"It clearly states that it's recommended for one at a time on a trampoline, but kids have half-a-dozen on there and that's where the trouble comes.
"You get two or three bouncing on it ... and if one person is in the wrong position at the wrong time the reaction from the mat will throw them."
If safety instructions were followed fewer accidents would occur, the spokesman said.
"But, kids will be kids."
Nationally, nearly 8400 injury claims relating to trampolines were accepted by ACC last year - about 160 a week - costing over $2 million.
A regional breakdown of injury costs was unavailable.
Most of the victims (84 per cent) were children aged 14 and under.
However, Kiwis in their twilight years also joined the fun - 16 injuries were logged for pensioners aged 70 and over.
The figures also indicate trampoline injuries are on the rise. Last year's national claim count was the highest in five years.
Jonathan Collins of Springfree Trampoline says children should be supervised at all times on trampolines.
"Broken bones are the most common injury, followed by bruising, sprains, cuts, dislocation and dental injury.
"The one at a time rule is important. A large number of injuries occur when multiple jumpers are on the trampoline and the smaller person is almost always the one injured."
Springfree Trampolines are said to be the world's safest - of the five trampolines tested in Consumer NZ's latest trampoline report, the Springfree was the only one to pass safety tests.
Mr Collins said falls and hitting trampoline frames and springs were the leading cause of injuries.
Consumer NZ has called for mandatory safety standards around trampolines. It also recommended current voluntary standards, which were last revised in 1997, be updated. An age breakdown shows injury numbers tapered off after the 10- to 14-year age bracket, but experienced a slight resurgence for those aged 35 to 44.
