Subject to several regulatory approvals, the deal would enable Virgin to launch flights within a year from Brisbane, Melbourne, Perth and Sydney to Doha, connecting into Qatar Airways' global network under a wet lease.

A wet lease involves one airline providing aircraft, complete crew, maintenance and insurance to another airline.

The measured return to long-haul international flights would begin in mid-2025, three years after Virgin started codesharing with Qatar Airways.

The deal would make the local airline more competitive and "inevitably" translate into more choice, better value airfares and more Australian jobs, Virgin's chief executive said.

"This partnership brings the missing piece to Virgin Australia's longer-term strategy and is a huge vote of confidence in Australian aviation," Jayne Hrdlicka said.

The addition of the cornerstone investor would also give Virgin and its shareholders scope to consider refloating on the Australian Securities Exchange.

The airline was delisted in 2020 after going into administration with almost $7 billion in debt before it was taken over by US-based private investment firm Bain.

"An IPO (float) would hopefully see lots of Australian institutions and retail investors joining Qatar as shareholders in Virgin Australia," Ms Hrdlicka told ABC TV.

The Transport Workers Union said any float should involve an employee share scheme.

That was among several demands workers wanted to address their reservations about Qatar Airways' influence over their jobs and working conditions.

"There are understandable doubts about this deal, particularly for cabin crew," union's national secretary Michael Kaine said.

"A commitment to respect is expected and necessary given Qatar Airways' track record."

With AAP.