Embattled Australian carrier Qantas said on Sunday it would hand out 100,000 free air tickets in a bid to win back passengers after the shock two-day grounding of its global fleet.

Some 70,000 travellers were stranded in 22 cities across the world when Qantas CEO Alan Joyce grounded the airline last Saturday to force an end to months of strike action by pilots, engineers and ground staff.

The gamble paid off for Joyce, with Canberra stepping in to prevent huge damage to the Australian economy by forcing an end to all industrial action at the airline, but furious passengers have vowed never to fly Qantas again.

The firm's woes deepened on Friday when an engine problem saw a Qantas A380 diverted to Dubai, in an unwelcome reminder of the engine explosion which temporarily grounded its entire superjumbo fleet exactly one year earlier.

Joyce kicked off a huge public relations offensive Sunday with the Aus$20 million (US$21 million) offer of a free return flight within Australia or between it and New Zealand for every customer stranded by last weekend's chaos.

"This ticket offer is one of a range of initiatives we will be launching as a way of saying sorry as we move forward into this period of stability," he said.

Some 100,000 tickets have been slated for the giveaway, and the offer is open for two years from December 14, with full-page newspaper advertisements urging passengers to "fly with us, on us".

Joyce said further announcements would soon be made about compensating overseas-based customers and its eight million frequent flyers.

Qantas has already promised to refund all "reasonable losses" for passengers affected by the drama, and spokeswoman Olivia Wirth said the airline would do "everything possible" to win back the public.

"We will be doing everything possible, bending over backwards, to make sure they continue to travel with Australia's national carrier, Qantas," she told reporters.

The pilots' union, which claims the airline is losing a 'pilot a day' to rivals such as Emirates, said it would have been "a lot cheaper for them to work with their workforce".

Tony Sheldon, head of the ground staff union, said it was mulling a court challenge to the strike ban this week, pending legal advice.

Joyce evoked national fury with his snap decision to shut down Qantas last weekend following several months of industrial action over the airline's plans to restructure its international business in Asia.

Staff want guarantees on job security, wages and conditions which Qantas rejects as unreasonable, and the once state-owned airline has warned that its future is at stake amid frenzied competition in the region.

Irish-born Joyce, 45, worked at rival carrier Ansett when it went to the wall in 2001, costing 17,000 jobs, and he said the experience had scarred him: "There were suicides, that was horrendous."

"There's no guarantee of the right to exist. You have to fight for it and I think that's what we're doing," he told the Sunday Telegraph newspaper.

He has been rounded on by politicians and the public alike, with the media dubbing him the nation's most loathed man, but Joyce said he was sick of what he described as 'racist' slurs about his accent and heritage.

"I don't think there's any difference between attacking somebody because of their Irish accent and attacking someone because of their colour -- they're all forms of racism," he said.