Uncapped duo of leg-spinner Tanveer Sangha and all-rounder Aaron Hardie have been picked in the squad, which would later be trimmed to 15, Cricket Australia said in a statement on Monday.
A five-match series in South Africa in September will be the first assignment of the Pat Cummins-led side, the cricket board said.
Labuschagne has played 30 of Australia's 38 matches since his debut in early 2020 and was part of the team that won a three-match series in India in March this year.
Mitchell Marsh, Cameron Green, Marcus Stoinis and Sean Abbott are the frontline seam-bowling all-rounders, while Ashton Agar and Sangha join Adam Zampa as their spin options.
Skipper Cummins sustained a wrist injury during the recent Ashes series that will keep him out of the three-match T20 series in South Africa preceding the one-dayers.
"We view a period of enforced rest for Pat as a positive ahead of this important World Cup campaign," Australia's selection chair George Bailey said in a statement.
"There are still a number of games he could play before the World Cup which is more than enough for him to have a strong preparation."
In his absence, Marsh will lead Australia in the T20 series in South Africa.
All-rounder Glenn Maxwell will miss the ODIs in South Africa as he expects the arrival of his first child, and will join the team in India for a three-match ODI series in September.
Five-time champions Australia will begin their World Cup campaign with an Oct. 8 clash with hosts India in Chennai.
Australia ODI squad: Pat Cummins (captain), 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
