The IRB backed new measures to protect players suffering from concussion and commissioned a major study into the risk of head injuries in the game.
Amid growing concern about the potential for high-impact sports to cause permanent brain injuries, the IRB said national rugby unions would trial the new measures in their domestic competitions.
Under the trial, players with suspected concussion will be sidelined for five minutes while they undergo a medical assessment by both the team doctor and an independent physician.
In a change from current rules, both the independent medic and the match referee will have the power to order the player from the field. The player will be temporarily replaced from the bench while the assessment is conducted.
"For the first time we are able to offer a standardised procedure of assessment that replaces an on-field 'on-the-run' assessment and is based on medical best practice," IRB chief medical officer Martin Raftery said.
"It provides an extra layer of protection for our athletes."
The New Zealand Rugby Union (NZRU) said the new measures would be used in this season's ITM Cup, the professional domestic league that is a tier down from the Super 15 competition.
The IRB also commissioned an Auckland University study that will examine the potential long-term effects of head knocks on rugby players.
The study will compare the neuro-psychological health of 200 former elite rugby players, 200 ex-community rugby players and 200 former athletes who did not play rugby.
In the United States, a major lawsuit involving more than 2,000 former National Football League players was filed in June accusing the NFL of ignoring and concealing the risk of brain injury, a claim the organisation denies.
Unlike in gridiron, rugby union players do not wear helmets during matches.
Raftery played down comparisons between rugby and gridiron, saying the NFL only banned hits to the head in 2010, while they had never been allowed in rugby union.
"The evidence supporting the theory that collision sports have a negative effect on cognitive function has been questioned by many scientists," he said.
"However, it is prudent to undertake these studies in order to broaden our understanding of concussion and ensure that we deliver the best possible player welfare framework for our athletes."
A study into concussion released last week by New Zealand's Massey University found many players and officials at last year's Rugby World Cup "appeared oblivious to the seriousness of such injuries".
After reviewing video footage of all the tournament's 48 matches, researchers said many players with suspected concussion were allowed to play on and were not sidelined for three weeks, as IRB rules stipulate.
It also found television commentators dismissed the impact of concussion, with one joking that a player was wobbling "like a drunken rhino" and offering advice such as "smelling salts, that ought to do the trick".
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