The University of Otago is also conducting a study to see if neck strength is a crucial factor in preventing concussion. Members of Otago's Mitre 10 Cup team wore electronic devices last season to measure impact forces.
But much of the work is focused on professional players, which risks ignoring the potential impacts on the tens of thousands who play in amateur games every week.
Labour's ACC spokeswoman Sue Moroney said the surging bill demanded an overhaul of injury prevention awareness.
ACC and NZ Rugby run a RugbySmart programme aimed to minimise injuries among amateur players.
Moroney said she believed the growing costs showed it wasn't effective enough.
"The programmes currently receiving Government funding aren't making a dent - they're demonstratively not working."
Moroney added rugby's growing popularity also meant even more should be spent on injury prevention.
The ACC figures show treatment for concussion has steadily increased from 1620 in 2012 to 2410 in 2015.
The most common rugby injuries were contusions and strains, followed by fractures and dislocations. Figures for 2016 are not yet available.
ACC sports injury prevention manager Isaac Carlson said despite the huge costs, he believed RugbySmart was effective.
Participation numbers were increasing and despite the rising cost of injuries, the number of serious injuries was reducing.
Tackling the serious issue of concussion was a key plank of RugbySmart, said Carlson.
"There's a lot more awareness now and I think the message has gone through," he said.
"The challenge now is that we know that it's an issue, what do we do about it? That's what RugbySmart will look to address."
Pakuranga United Rugby Club premier player Jean-Pierre Potgieter broke his leg in a game in July last year.
His ACC-funded treatment included a cast for six weeks and 12 weeks of physio.
He said rugby players suffered a high number of injuries, because of the game's physical nature.
Potgieter, who has a sports science degree and works as a personal trainer, said players also had a responsibility to look after themselves.
But pressure of work meant that was often not possible.
"I'm in the gym all day, every day anyway for my job, so for me, it's easy to put in that work.
"But when you're working eight hours a day, when you have your nights off from rugby, you don't want to be in the gym."