Rugby's Tri-Nations could become the Four-Nations after Argentina 's conditional invitation to join South Africa New Zealand and Australia from 2012.
Rugby officials in Argentina are enthusiastic but the Tri-Nations' governing body SANZAR says their top players will have to turn out for the Pumas, meaning they will have to shift from the clubs in Europe where most of them play.
The other option there is for the players and the clubs to be financially compensated while the Pumas are away on Test duty, as the competition will be played outside the IRB's international window.
SANZAR say they'll work with Argentina to place their best players throughout the Super 15 franchises, but New Zealand rugby union chief executive Steve Tew says the details of that plan are still to be worked out.
SANZAR's chief executive Andy Marinos says there are also complex financial and broadcasting matters to be sorted out.
The New Zealand rugby union is confident Argentina will meet all the necessary requirements to join the southern hemisphere competition.