New Zealand's leading coaches and other prominent rugby figures are set to discuss a range of possible rule changes in the next weeks, after two recent incidents highlighted fears for player safety when competing for the high ball.
Last weekend, Blues fullback Matt Duffie was hurt colliding with Crusaders wing Manasa Mataele while competing in the air, and Highlander Tevita Nabura was red-carded for leading with a high foot which connected with Waratah Cameron Clark.
The Duffie incident at Eden Park left Blues coach Tana Umaga outraged, with the fullback forced off with injury in the 32-24 defeat.
Duffie expressed his frustrations to Umaga, saying: "Should I go up for high balls if I'm going to come down like that all the time?"
The officials decided Mataele's challenge was fair because he had eyes only for the ball, and yet Duffie was in a more dominant, higher position and fell heavily.
Nabura's act early in the Highlanders' 41-12 defeat in Sydney - that saw him suspended on Friday for six weeks - was judged to be one by an inexperienced player and yet many players practice jumping with a leg outstretched towards the opposition for balance and protection.
The Herald on Sunday understands that coaches and players at every level of the professional game, including the All Blacks, have become increasingly concerned with and frustrated by referees' perceived inability to follow World Rugby's "zero tolerance policy to any attacking player who makes contact with a leaping defender".
One of the possibilities being discussed is whether the only way to guarantee safety in this area is to stop players jumping at all.
Taking away such competition would be a drastic step for a game which places the utmost importance on the battle for possession, and that was a theme stressed by All Blacks and Highlanders fullback Ben Smith, one of the best in the game under the high ball.
"There still needs to be a contest - that's part of the game," Smith told the Herald on Sunday. "If you take away the contest ... you can't have that because that whole part of the game will be taken away. I can't really see that happening.
"Consistency [of ruling] is probably the main thing. It's a tough one because when you go up for a high ball, you just have to make sure you're protecting yourself. I suppose sometimes ... it can look bad. It's a matter of making sure the tackler is being careful of the guy in the air. Both players have to be careful."
●Meanwhile, World Rugby is to introduce a trial law change at under-20 competitions that lowers the height of tackle to "below the nipple line" to reduce the risk of head injury.
The current height for a legal tackle is in line with the shoulders. But after research revealed 76 per cent of head injuries occurred in the tackle, World Rugby believes the change could reduce risks, particularly of concussion. The trial aims to change player behaviour through revised on-field and off-field sanctions.
It was approved after a study of 1500 games that concluded that the "risk of injury to both players from a high-contact tackle (when the tackler is upright) is 4.3 times greater than a low-contact tackle".
At the Under-20 Championship in France, which starts next week, a high tackle warning will be issued if the tackler does not bend at the waist when tackling and there is clear head contact for either player. Two high-tackle warnings for the same player will trigger a one-match ban.