World Rugby has unanimously approved a recommendation that unions participate in trials of 'belly tackles' in the community game to reduce concussions.
A belly tackle is a tackle made at a height below the sternum (mid chest).
The opt-in trial aims to improve player safety by reducing head-on-head contact, with the results to be reviewed in early 2025.
"We anticipate that the trial will take time to settle," said World Rugby chairman Sir Bill Beaumont.
"However, throughout this process we have been guided by the science to help make the game safer for our players and the evidence is unequivocal."
The governing body's council ratified a recommendation by its executive board in March relating to the community game, which covers clubs, schools, colleges and universities. Similar trials are already taking place in France and New Zealand.
England's Rugby Football Union (RFU) announced in January that players will only be able to tackle from the waist down from July in the community game, impacting age-grade and adult levels - from National One and below in the men's game and Championship One and below in the women's game.
The new trial will allow member nations the freedom to set a legal tackle height at the base of the sternum or below - as best suits their community game - and also set secondary laws governing associated areas of the game such as pick and go, double tacklers and ball carriers dipping into contact.
World Rugby added that, following enquiries from members, they would support closed trials at the elite level should a union or competition wish to run one.
The governing body has pledged to support players and unions with coach and player education tools, such as free training modules, as well as ensuring that trials are properly assessed and monitored.
"World Rugby will continue to support unions throughout the next two years in educating players, collecting data and analysing research so that our decision making continues to be informed by the best possible evidence," added Mark Harrington, the organisation's chief player welfare and rugby services officer.