Players wishing to switch nationality in time for next year's Rugby World Cup will have to play in at least four tournaments on the upcoming World Sevens Series.
The International Rugby Board has released a three-page document clarifying the rules around players wishing to turn out for a second country.
Fiji, Samoa and Tonga have all expressed their desire to use the eligibility laws to their advantage, and have held discussions with a number of players, including former All Blacks and Wallabies.
The IRB's Regulations Committee says a player must appear in at least one leg of the upcoming IRB sevens series for their new nation to qualify for the 2016 Olympics, but need to play in at least four world series tournaments to be eligible for fifteens.
The document also states that players will not be able to revert to their former Union should their application to play for a second Union fall through.
The stand down period for sevens representation is 18 months and three years for fifteens.