World Rugby has agreed to a new amendment that will allow players transfer national allegiance during their careers.
The proposal, which has been termed as a 'landmark' change, will help improve the 'global competitiveness of rugby', according to the governing body.
The new rule will allow those who have a 'close and credible link' to another country to transfer, once they have been stood down from international rugby for three years.
In order to be eligible to transfer, the player must have been born in the country they are transferring to, or have a parent or grandparent who was born in that country.
Players will only be allowed to change union once, and each case will be subject to approval by a World Rugby committee to 'preserve integrity'.
World Rugby Chairman Sir Bill Beaumont said: “Approval of this landmark regulatory change is the culmination of detailed and widespread modelling and consultation across the game.
"We have listened to our membership and players and sought to update the regulation recognising the modern professional rugby environment without compromising the integrity of the international game.
“Any player who wishes to transfer will need to have a close and credible link to their new union, namely birth right or parent or grandparent birth right while meeting strong criteria, including a 36-month stand down period.
"We believe that this is the fairest way to implement progressive change that puts players first while also having the potential to support a growing, increasingly competitive international men’s and women’s game.”
International Rugby Players CEO, Omar Hassanein hailed the possible impact the decision could have, particularly for smaller countries.
“The proposal to change the rules around player eligibility is something that we have worked on over many years with our member associations," he said.
"Many players across the world will now benefit from the chance to represent the country of their or their ancestors' birth, serving as a real boost to the competitiveness of emerging nations, which in turn, will benefit the game as a whole.”
The new regulations will come into force from January 1st this year.