SYDNEY, AUSTRALIA - JANUARY 22: Mitchell Starc of Australia (L) celebrates with Steve Smith (C) and Pat Cummins (R) after taking the wicket of Umar Akmal of Pakistan during game four of the One Day International series between Australia and Pakistan at Sydney Cricket Ground on January 22, 2017 in Sydney, Australia. (Photo by Matt King/Getty Images)

Australia have revealed their extended squad for the ODI World Cup, with the surprise call made to drop Marnus Labuschagne.

The 18-man squad will be trimmed before the World Cup to 15 under ICC rules - the cut off date for those changes is on September 28, just seven days before the first ball of the World Cup on October 5.

It's Labuschagne's status as an unselected batsmen which will surprise the majority, although the elevation of potential debutants Tanveer Sangha and Aaron Hardie is also unexpected.

The squad will play five ODIs in South Africa during early September and three more against India in late September right before the cut off date before squad changes and trimmings have to be locked in.

It gives Australia eight ODIs to work through their final squad before the World Cup, and there will be opportunities, with regular XI members Pat Cummins (wrist injury) and Glenn Maxwell (birth of his child) to miss the tour of South Africa.

That will leave 16 players fit for the tour of South Africa, and it's anticipated that, coming off the Ashes, many of the multi-format players - being Alex Carey, Cameron Green, Josh Hazlewood, Travis Head, Steve Smith, Mitchell Starc and David Warner - won't play all five games.

The other members of the squad include wicket keeping option Josh Inglis, all-rounders Ashton Agar, Mitchell Marsh and Marcus Stoinis, while bowling options Sean Abbott, Nathan Ellis and Adam Zampa have also been included alongside Hardie and Sangha.

"This side has been extremely impressive for several years in limited-overs cricket," chief selector George Bailey said.

"There is an enormous amount of skill and experience in the group, which you need in a World Cup."

Australia's extended 18-man squad for the ODI World Cup

Pat Cummins (c), Sean Abbott, Ashton Agar, Alex Carey, Nathan Ellis, Cameron Green, Aaron Hardie, Josh Hazlewood, Travis Head, Josh Inglis, Mitchell Marsh, Glenn Maxwell, Tanveer Sangha, Steve Smith, Mitchell Starc, Marcus Stoinis, David Warner, Adam Zampa

Three to be ommitted following ODIs vs South Africa and India.