A doctor says suggestions children should be banned from playing contact sport because of concussion risks go too far.

Neuroscientist Dr Chris Nowinski told TVNZ sports, including rugby, should be restricted in under 14s, to avoid repeated head knocks.

But former All Black and Warriors team doctor John Mayhew told Mike Hosking that won't prevent children getting concussed.

"Children do other things - mountain biking, they go down skateboard ramps - and they bang their heads in other ways. I think we've got to minimise the number of head clashes occuring in all contact sports but to ban it, I think, is over the top and not necessary."

LISTEN ABOVE