The multi-billion-dollar commitment, which confirmed an earlier report by Reuters, was announced at the Singapore Airshow, making it one of the biggest deals so far at Asia's largest aerospace event.

Demand for wide-body jets is surging as air travel rebounds after the pandemic, though the air show has been overshadowed by a warning from home carrier Singapore Airlines that fares are now coming under pressure from overcapacity.

Qantas Airways and Air New Zealand on Thursday flagged delays to deliveries of Airbus A350 and Boeing 787 jets respectively, as manufacturers struggle with supply chain issues.

Deliveries of VietJet's new planes will start from 2026, and the deal is expected to become a firm order in a few weeks, said Airbus commercial aircraft executive vice president of sales Benoit de Saint-Exupery.

VietJet, one of Asia's largest low-cost carriers, said the A330-900 order will replace is fleet of leased A330-300s - an earlier model. This will be VietJet's first wide-body purchase.

Airbus is anxious to prolong sales of its A330neo as it amortises upgrade costs and preserves its longstanding A330 line, which the newer A350 is gradually superseding.

The latest deal highlights the growth of VietJet, which said on Wednesday it is expanding in destinations such as Australia, India, China, Japan, South Korea, Indonesia and Thailand.

The carrier has some 108 Airbus jets and 200 Boeing jets on order, according to the two planemakers' websites.

(Reporting by Khanh Vu in Hanoi and Lisa Barrington and Brenda Goh in Singapore; Editing by Gerry Doyle and Jamie Freed)