The hip-drop, until now conspicuously absent from the code's rule book, will be defined as dangerous play after a series of serious injuries prompted calls from within the Australian rugby union community to ban it.
Discussed at World Rugby's Shape of the Game summit in February, the hip-drop will be banned from November 1 ahead of the remaining Nations Championship Tests.
The knee-drop tackle, where a player drops to one or both knees before making a tackle, is already covered in law but has also been highlighted as an area of focus.
It comes after Penrith's Dally M-winning halfback Cleary suffered a compound fracture in a hip-drop tackle in an NRL preliminary final two weeks ago, with tackler Phoenix Crossland accepting a four-week ban.
Kansas City Chiefs wide receiver Tyquan Thornton also copped an ugly, long-term ankle injury when tackled in a similar fashion in the NFL against Las Vegas this week.
Raiders defensive back Treydan Stukes faces a heavy fine or suspension for his actions.
Emerging Queensland Reds talent Treyvon Pritchard, Wallabies winger Max Jorgensen, All Blacks scrumhalf Cam Roigard and Brumbies hooker Lachlan Lonergan have all been injured in hip-drop tackles in the the last two years.
That prompted repeated criticism from Australian coaches and officials, with Reds football boss Sam Cordingley critical of the lack of action on a lazy technique that carried "catastrophic" consequences.
Hip-drops were outlawed by the NRL in 2020 and were already banned in New Zealand's junior and community rugby competitions.
"We're grateful to unions for raising the issue of these types of tackles with us," Australia's World Rugby chairman Brett Robinson said.
"Once we looked at the evidence, it was clear the hip drop tackles whilst rare, could cause significant leg injuries. It was also clear that knee drop tackles were on the rise.
"Protecting player welfare is at the heart of everything that World Rugby does and once we'd reviewed the analysis we've acted quickly to ensure that dangerous tackles of this nature are removed from the game."
A hip-drop tackle will penalised and, in serious cases, referred to a judiciary, when a ball carrier is grasped and tackled from the side or behind and the tackler swings around or through the ball carrier and drops their weight on their legs.
A knee-drop tackle will be ruled when a defender drops to one or both knees before making a tackle.
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