World Rugby is considering introducing a rule whereby teams that kick from their own half to the opponents' 22 would get possession at the line-out.

The rule, based on an existing Rugby League regulation, would award a line-out to a team that kicks from their own half if the ball bounces in play before crossing the touch line in the opposition 22. Such a kick currently gives the throw-in to the other team.

The thinking behind the change would be to encourage teams to keep more players deeper down the field to try and gather the kick, thereby lessening the attractiveness of the massed 'rush' or 'blitz' defence - World Rugby says that tackles account for 76% of concussions sustained on the field, 72% of affecting the tackler.

"Rather than just look at the laws and whether it has a player welfare impact, we have tried to devise laws that have a direct player welfare impact. That's the first time we've looked at it in that sense," World Rugby chief executive Brett Gosper told the Times of London.

"Some of the experiments we are seeing here about opening up the game and creating more space can limit the number of collision events and therefore drive some of the statistics down."

Another proposal would allow citing commissioners to review yellow cards during a game, with the ability to upgrade the punishment to a red during the 10-minute sin-bin period.

There a total of eight proposals that will be debated in May for possible introduction in 2020; tweaks to the offside line, rucks and number of substitutions will also be discussed.