Michael Cheika announces Wallabies' 31-man Rugby World Cup squad

Wallabies coach Michael Cheika has taken a huge gamble, picking just two halfbacks in his 31-man Rugby World Cup squad, while including injury prone teenager Jordan Petaia and underdone veteran flanker David Pocock.

Nineteen-year-old Reds utility back Petaia has made a huge impression since debuting for the Reds but his selection must be considered a risk considering he has sat out the majority of 2019 with a foot injury.

His selection puts him in line to be the youngest Australian ever to feature in a World Cup tournament.

Pocock, meanwhile, was forced into an early Super Rugby retirement after a troublesome calf injury sidelined him in January. He has not played for the Brumbies or the Wallabies since and question marks remain over his role in Japan with skipper Michael Hooper a fixture in his favoured No.7 jersey.

Cheika and the Wallabies selectors went for a split of 17 forwards and 14 backs, leaving Will Genia and Nick White to fight it out for the all-important No.9 jersey - a specialised position that is more often than not covered by three players for World Cups.

The Brumbies, Rebels and Waratahs have eight players each in the squad and the Reds six.

Eighteen of the squad will be playing in their first World Cup but the inclusion of Adam Ashley Cooper for his fourth World Cup and redeemed former golden boy James O'Connor adds significant Test experience.

"We've become a really tight group and it was a very difficult process in picking only 31 players, but I know each player selected will travel to Japan with the full support of those teammates who won't board the flight," Cheika said.

"We have worked really hard at building each week and each game so far this season, and play a brand of rugby that Australia would be proud of and get every player contributing towards the outcome.

"It's also important that we select a squad that will handle the tournament play and our draw in particular at the Rugby World Cup, as well as maintain a strong competition for places in the team."

Wallabies World Cup squad:

Michael Hooper (c), Samu Kerevi (vc), Alan Alaalatoa, Rory Arnold, Adam Ashley Cooper, Kurtley Beale, Adam Coleman, Jack Dempsey, Folau Fainga'a, Bernard Foley, Will Genia, Dane Haylett-Petty, Reece Hodge, Sekope Kepu, Marika Koroibete, Tevita Kuridrani, Tolu Latu, Christian Lealiifano, Isi Naisarani, James O'Connor, Jordan Petaia, David Pocock, Izack Rodda, Lukan Salakaia-Loto, Rob Simmons, Scott Sio, James Slipper, Matt Toomua, Taniela Tupou, Jordan Uelese, Nick White.

The Wallabies will play a final warm-up game against Samoa on September 7 before boarding a plane for Japan where they will begin their World Cup campaign against Fiji on September 21.

Warm-up game

Wallabies v Samoa at Bankwest Stadium, Parramatta, Saturday 7 September at 7.30pm AEST

Australia's 2019 Rugby World Cup pool fixtures

Wallabies v Fiji at Sapporo Dome, Sapporo, Japan, Saturday 21 September at 2.45pm AEST

Wallabies v Wales at Ajinomoto Stadium, Tokyo, Sunday 29 September at 5.45pm AEST

Wallabies v Uruguay at Oita Bank Dome, Oita, Saturday 5 October at 3.15pm AEST

Wallabies v Georgia at Shizuoka Stadium, Shizuoka, Friday 11 October at 9.15pm AEST