Last updated 05:00 21/07/2014
A loophole in the International Rugby Board's player eligibility rules could see some players change national allegiance ahead of the 2015 Rugby World Cup.
One man who could theoretically switch allegiance is cross-code superstar Sonny Bill Williams, if he chose to represent Samoa instead of New Zealand.
Frank Halai, Isaia Toeava and Joe Rokocoko could also switch allegiance to Tonga, Samoa or Fiji respectively, if they chose to represent the nation of their birth.
The loophole comes about because of the inclusion of rugby sevens at the 2016 Rio Olympics, and rules stating that to compete for a country you must have that nation's passport.
According to the IRB Handbook, Regulation 8, any player that has represented a national team, but has a passport for a second country, can switch allegiance during the 2014-15 IRB Sevens World Series if there has been an 18-month period since their last national team appearance.
To become eligible for a second country, the player must apply to switch allegiance, and then turn out for his new country during next season's World Series, which doubles as Olympic qualification.
The player can only debut for his new team once the application is approved, and once the 18-month national team stand-down has passed.
Once a player has made his sevens debut for a new national team in an Olympic event, like the 2014-15 World Series, IRB rules state that the player can then play any form of the game for his new country.
For instance, Sonny Bill Williams last played for the All Blacks on August 25, 2012, in a 22-0 win over Australia at Eden Park.
If he chose to switch allegiance to Samoa, of which he holds a passport, he could debut for Samoa when the IRB Sevens World Series starts later this year.
He could then play for Samoa at the 2015 Rugby World Cup, and represent Samoa at the Rio Olympics.
Williams won't be changing allegiance, and has shown no signs of wanting to switch, having signed a two-year deal with New Zealand Rugby and the Chiefs Super Rugby franchise.
Likewise, Frank Halai won't be switching allegiance, with his chances of playing for New Zealand at the 2015 World Cup and Rio Olympics still high.
However, players like Isaia Toeava, Joe Rokocoko or Sitiveni Sivivatu could make the switch with no future in the All Blacks or with the New Zealand Sevens team.
Toeava, 28, would be an interesting prospect for Samoa, having played his last game for the All Blacks at the 2011 World Cup.
Rokocoko is only 31 and playing well in France, and Fiji would surely be interested in someone of his ability and experience.
Other players who could theoretically switch nations are one-cap All Black and 2006 Commonwealth Games gold medallist Soseni Anesi (Samoa), three-test All Black Benson Stanley (Australia) and 14-test England international Riki Flutey could switch allegiance back to New Zealand.
The next chance players will have to switch allegiance will be during the 2018-19 IRB Sevens World Series, doubling as a qualifying event for the 2020 Tokyo Olympics.
From then on the stand-down period for players will be extended to three-years, rather than the 18 months this coming season.
Full rules around eligibility can be found at Regulation 8 of the IRB Handbook
- Waikato Times