NSW teen unconscious after nasty hoverboard accident

A NSW teen is in hospital after a nasty accident involving this year's must-have Christmas gift, a hoverboard.

The 16-year-old was knocked unconscious after a fall while trying out the board and had to be rushed by ambulance to a waiting rescue helicopter at Elanora Heights on Sydney's northern beaches.

"He began to revive just as the specialist CareFlight doctor and intensive care paramedic were about to begin urgent treatment for an isolated head injury," CareFlight said in a statement on Friday.

The medics then moved the boy by ambulance to Royal North Shore Hospital where he's undergoing tests.

CareFlight said the boy's accident "gave his family a scare".

Hoverboards look like skateboards but with larger wheels and are designed to mimic the levitating boards which featured in the smash hit Back to the Future films of the 1990s.

They've been a popular item for youngsters this Christmas and can cost up to $2000, despite being prohibited for use in public in NSW and many other places around the world.

Serious safety concerns have also been raised about some makes of the item, with reports that the device can explode.

Earlier this year a grandfather in the UK was left with $50,000 worth of damage to his home after the board he bought for his grandchild exploded in his home.