Qantas will order 10 Airbus SE A321XLR jets, taking its total A320neo family order to 109 jets.
As part of the deal, 36 of the jets will be the new long-range A321XLR model, the airline said on Wednesday.
The A321XLR jets, to be delivered from mid-2024, have a 4,700 nautical mile range that will allow Qantas or its low-cost arm Jetstar to perform longer-range flights in narrowbody jets.
"It can fly routes like Cairns-Tokyo or Melbourne-Singapore, which existing narrow-bodies can't, and that changes the economics of lots of potential routes into Asia to make them not just physically possible but financially attractive," Qantas chief executive Alan Joyce said in a statement.
Jetstar operates an A320 narrowbody fleet, but Qantas uses the rival Boeing 737.
Joyce said the A321XLR had plenty of potential uses across both airlines and it would decide closer to the date on where they would be deployed and if they would be used for growth or to replace older jets.
Jetstar is due to receive 18 A321LR jets from 2020 to 2022 and plans to deploy them on domestic and international routes.
The additional 10 jets are valued at more than $US1 billion ($A1.45 billion) at Airbus list prices, although airlines typically receive substantial discounts.
Qantas said it retained flexibility around the timing and structure of the deliveries depending on market conditions.
Qantas is expected to decide next year on a replacement for its 75 737 jets, which comprise the backbone of its domestic fleet, Joyce said in February.
Contenders include the A320neo family, the 737 MAX and Boeing's proposed new mid-sized airplane.
