World Rugby has announced that, with immediate effect, it will no longer be possible to score a try by grounding the ball against the post protector.
The law change was approved by the World Rugby Council during its special meeting held via teleconference today and follows a recommendation by the international federation's Rugby Committee and specialist Laws Review Group.
The rationale for the law change was that it had become too difficult for teams to defend the area immediately in front of the post-protector from close-in ruck situations.
Post-protector have increased in size and shape in recent years for welfare reasons but this has put added pressure on defences.
In their statement World Rugby referenced instances of defending teams lifting the post-protector to prevent such tries being scored, the most notable example occurring when Edinburgh used this tactic when defending frantically against Munster in a game last November.
The new law states that the post-protector is no longer an extension of the goal-line.
World Rugby Chairman Sir Bill Beaumont said: "World Rugby's mission is to make the game as simple, safe and enjoyable to play as possible. This law amendment reflects that mission.
"By stipulating that an attacking team can no longer score against the post protector and therefore must ground the ball in-goal, this gives defending teams a fair chance of preventing a try from being scored."