Quade Cooper admits he faces a big challenge to establish himself in Australia’s rugby sevens team for the Rio Olympics.

France-based Cooper returned to Sydney on Tuesday and immediately began training with the Australian squad for his debut in this weekend’s Sevens World Series round at Allianz Stadium.

The former Wallaby playmaker has only secured a release from his club Toulon to play in three rounds of the World Series, giving him little time to adapt to the very different tactics and demands of the high-paced sevens game.

“It’s a game I haven’t played much of and I am under no illusions that is is going to be difficult,” Cooper said.