The next Tongan Thor will have to spend five years on Australian shores before being eligible for Test rugby, under new laws passed by World Rugby.
World Rugby's executive met in Tokyo ahead of the Rugby World Cup 2019 draw, passing the new regulation eight laws, extending a three-year eligibility criteria to five years.
The law will come into effect from Jan 1, 2021, with players having to live continuously in a country for five years before being able to be selected.
Winger Sefa Naivalu is the most recent Wallaby debutant who has come to Test rugby, after moving to Australia from Fiji.
World Rugby chairman Bill Beaumont said the change was about reinforcing the integrity.
"This reform of Regulation 8 governing eligibility is an important and necessary step to protecting the integrity and credibility of international rugby," he said.
"This extension to the residency period within a forward-thinking reform package will ensure a close, credible and established link between a union and players, which is good for rugby and good for fans.
“I would like to thank my union colleagues for their support and in particular the leadership role that Agustín Pichot played in this very important process that has delivered an outcome that is good for the global game.”
Vice-chairman Agustin Pichot said the move was one would ensure players are 'devoted' to the countries they represent.
“This is an historic moment for the sport and a great step towards protecting the integrity, ethos and stature of international rugby," he said.
“National team representation is the reward for devoting your career, your rugby life, to your nation and these amendments will ensure that the international arena is full of players devoted to their nation, who got there on merit.”