About a sixth of head and face injuries sustained while playing rugby or netball were to children 12 and under, new figures show.
The data - which doesn't include professional athletes - comes on the heels of the world's leading experts in head injuries saying children under 12 should not play contact sports.
ACC figures showed there were 5994 head injury claims made for those 12 and under from playing netball, rugby league or rugby union between 2015 and the end of April this year - 16 per cent of the total head injury claims made for those sports. About half of all the players in those sports are within that age group.
The claims would include any injury to a player's head or face mentioned when filling out an ACC form, or an injury which had a concussion diagnosis.
Data showed the amount paid out for head and face injury claims sustained by children 12 and under playing the three sports during that time period totalled $1,387,783 – 3.9 per cent of the total amount claimed across all age groups.
Since 2015, 606 children made an ACC claim for a head injury sustained while playing netball, 1188 for rugby league and 4200 for rugby union.
Earlier this month, a group of Boston scientists told the Herald research showed the younger you started sports like rugby and American football, the greater your chances of suffering degenerative brain diseases.
The scientists, including the "Godfather of Concussion" Dr Bob Cantu, said new research showed repeated ordinary hits were responsible for the high number of NFL players with signs of the incurable brain disease chronic traumatic encephalopathy - not just the big hits which caused concussion.
It was those findings which led to them encouraging parents not to let their children play contact sport until they were 12.
ACC figures showed 15.9 per cent of head injuries in rugby union were to those 12 and under but New Zealand Rugby head of participation and development Steve Lancaster said that was a tiny proportion of players.
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"The risks of head injury in junior rugby are very low – we know that about 1.2 per cent of players 12 and under claim an injury to the head or face each year."
He said the increased awareness about preventing and managing injuries had resulted in more being reported in the last few years but he hoped the current focus on technique would see those numbers drop again.
It appeared that trend may have begun last year, he said. Figures showed the number of head injuries across all ages dropped from 7002 to 5818.
As for league, almost 17 per cent of head injuries were in players 12 and under but New Zealand Rugby League said that age group made up 46 per cent of players.
New Zealand Rugby League general manager of football and wellbeing Nigel Vagana said the organisation had been working hard to educate players, staff and volunteers about ways to avoid and deal with injuries.
A concussion protocol developed last year had since been implemented and included a strict stand-down policy, he said.
"We also have a philosophy at NZRL called 'If in doubt check it out' where we'd rather be safe than sorry, so even the tiniest concern, we always recommend getting a medical check."
ACC figures for netball showed about 18 per cent of all head injuries in the sport were among the 12 and under age group which made up about 48 per cent of players.
Netball New Zealand's NetballSmart programme manager Sharon Kearney said the organisation was focused on raising awareness about all injuries - including concussions.
But, she said, statistics provided to the organisation showed there were only 186 concussions reported to ACC last year - 0.6 per cent of the total number of netball injuries.
"Head injuries could be a cut, a graze, a poke in the eye, a broken nose," she said.
Starting out young
"If you picked up rugby, league or netball at high school level and had never played before, the risk would be higher."
That's one mum's take on contact sports.
Kelly Albrecht's four kids, aged between 9 and 5, all play rugby with some playing league and netball as well.
The youngest has just started playing rippa rugby, the non-contact version of the sport, which her siblings also started in.
Albrecht said they signed their kids up for rippa rugby because it was non-contact and they wanted to build their co-ordination and teach them to work as a team.
But the kids all loved the sport so much they were keen to move up to full contact rugby when they were old enough.
"My husband and I had some concerns. Concussion always comes up," she said. "But if you limit your children because of your insecurity about the sport, it limits their ability to grow".
Instead they bought them all headgear and mouth guards to lessen the damage caused by a decent knock and made sure they had coaches who taught correct techniques for tackling safely.
Albrecht said there was now a real consciousness about the possibility of concussion and coaches were quick to sub a child off so they could assess the player if they were unsure.