(Reuters) -Qatar Airways plans to buy a 25% stake in Australia's No. 2 airline Virgin Australia from U.S. private equity firm Bain Capital, the companies said in a joint statement on Tuesday.

The purchase of the minority stake for an undisclosed amount will serve as a cornerstone investment ahead of an anticipated return of Virgin Australia into public ownership, the companies added.

Bain said last year that it would explore an initial public offering of Virgin Australia, which it bought for A$3.5 billion ($2.42 billion) including liabilities after it was placed in voluntary administration in 2020.

Bain was targeting an A$1 billion listing, but the plans were delayed, Reuters reported last year.

Virgin Australia CEO Jayne Hrdlicka said the partnership with Qatar Airways brought a "missing piece" to the Australian airline's longer-term strategy.

"It will further strengthen Virgin Australia's ability to compete over the long term, which will inevitably translate into more choice and even better value airfares for consumers," she said in a statement.

The deal remains subject to regulatory approvals, including from Australia's Foreign Investment Review Board.

Qatar Airways has previously been stymied in its attempt to increase flights from Australia, with its plans blocked by the government last year.

The decision brought the Australian government's relationship with Qantas Airways into the limelight. Qantas and Virgin Australia together control about 90% of the country's domestic aviation market.

As part of the deal with Qatar Airways, Virgin Australia plans to launch flights from Brisbane, Melbourne, Perth and Sydney to Doha with leased aircraft by mid-2025, subject to approval from Australia's competition regulator.

That would allow Qatar to gain more traffic to its Doha hub, regardless of whether the Australian government approves Qatar Airways' push for more flying rights.

Qatar Airways also owns minority stakes in British Airways owner IAG, Hong Kong's Cathay Pacific Airways and China Southern Airlines.

($1 = 1.4474 Australian dollars)