Club rugby player Willie Halaifonua, 27, died from a brain bleed last month after collapsing with a head injury at the end of a premier division match at Auckland's North Shore, and a 17-year-old rugby player remains in an induced coma after suffering a head injury on Saturday during a high school match in Dunedin.
Mr Cobb said players' head injuries were taken very seriously.
If any one of Wanganui's 3200 registered players received a concussion, they faced a stand-down period of three to four weeks. More than one concussion a season "spelled the end" of that season.
Rugby copped its fair share of criticism, especially as the game evolved, he said.
"Scientists keep coming up with these theories that put paranoia in the heads of the public.
"It is a concern for us ... because it doesn't portray positively on the game."
The game itself was getting faster and the knocks were getting harder, he said.
And when tragedies like Halaifonua's death occurred, the rugby world got a real shake-up.
"But people still want to play, so we have a duty of care to provide that safety net for players."
ACC received 429 Wanganui claims for rugby-related injuries last year at a total cost of more than $1 million - 115 fewer claims than 2011.
National Dementia Co-operative chairwoman Dr Chris Perkins said the impacts of boxers' head injuries were well documented, but the same principle could apply to other high-impact sports like rugby.
"It's one of the known facts that if you get too many head injuries, you end up with dementia
"Apart from the fact it's a brain injury, it leaves you with less brain reserve."
Wearing helmets could help protect rugby players from head injuries, but the advantages of physical activity had to be weighed against injury risk.