Argentina have been given a conditional invitation to join Tri-Nations teams South Africa, New Zealand and Australia in an expanded "Four Nations" championship from 2012, rugby officials said.

The long-awaited move to revitalise the competition comes just days after world champions South Africa sealed the 14th edition with victory over New Zealand.

"To have the Pumas... join with the three top-ranked international teams in world rugby will be exciting for fans, players, sponsors and broadcasters across our four countries and beyond," SANZAR chief Andy Marinos said in a statement.

"They play a different style to the All Blacks, Springboks and Wallabies and their inclusion will see the Tri-Nations evolve to be a truly southern hemisphere championship."

Argentina's entry depends on a commitment to send their best players and on confirming the financial set-up with South Africa, New Zealand and Australian Rugby (SANZAR), which also needs to consult with its broadcasters.

Argentina have been seeking entry to an elite tournament but have so far been unsuccessful in joining Europe's Six Nations or the Tri-Nations.

The Pumas are ranked sixth in the world and finished third at the 2007 World Cup, but say they have been held back by their lack of regular top-flight competition.