Tens of thousands of passengers were stranded around the world Sunday after Australian airline Qantas made a shock decision to ground its fleet indefinitely in a bid to end a bitter industrial dispute.

Stunned flyers who had been booked on Qantas queued up at airports around the world to find out when they might be able to fly, after the national carrier announced the extraordinary shutdown of all its flights.

"I am very surprised they are not flying," one French-speaking passenger said in Sydney after turning up for a flight to Noumea only to learn of the lockout of staff and grounding of the fleet announced late Saturday.

"We have been told nothing. I just want to get home but I don't know how or when I can do this," she said as she stood near empty Qantas check-in desks.

Qantas chief executive Alan Joyce said the airline, which has been hit by a series of strikes, would lock out all employees involved in industrial action from Monday evening without pay and ground flights from 0600 GMT Saturday.

The airline said pilots, engineers and baggage, ground and catering staff involved in the industrial action were essential to Qantas operations and their lockout made it necessary to take all planes out of service immediately.

Aircraft would remain grounded "as long as it takes to reach a conclusion on this," Joyce said, vowing not to bow to union demands for a pay increase and to abandon a plan to shift Qantas' operational focus to Asia.

"That would destroy Qantas in the long term. I'm actually taking the bold decision, an unbelievable decision, a very hard decision, to ground this airline," he said late Saturday.

Up to 80,000 passengers were stranded when 108 aircraft were grounded at 22 airports around the world as Qantas took the drastic step.

The move prompted immediate intervention by the Australian government, which took the rare step of asking the industrial umpire to terminate all industrial action because of the dangers posed to the national economy.

"I believe Australians want to see this sorted out," Prime Minister Julia Gillard said.

"Businesses want to see it sorted out. Passengers want to see it sorted out. I want to see this dispute sorted out. That's why we have approached Fair Work Australia."

In its submission to the labour relations tribunal, the government asked for the industrial action to be terminated or suspended for 90 days.

The tribunal's hearing ran into the early hours of Sunday morning, hearing submissions from both sides in the escalating dispute, but adjourned the hearing until 2:00pm (0300 GMT).

Qantas is urging Fair Work Australia to terminate all industrial action, but unions want the action suspended to give both sides a chance to resolve the conflict.

But Joyce said Sunday the airline would not put its planes back in the air unless the industrial arbiter terminated all industrial action, ending the strikes that he said were "slowly killing" the carrier.

"A suspension may not necessarily mean the airline gets back in the air. If it's a suspension, we cannot put the planes back in the air without having certainty," Joyce told Sky News.

If the regulator terminates action on both sides, planes could be back in the air late Sunday, Joyce said, ending the lockout that he said was a last resort aimed at limiting further damage to Qantas.

Unions have been protesting against pay and restructuring plans that would see 1,000 jobs axed and the establishment of two new airlines focused on Asia. Unions fear many jobs will be outsourced to Asia.

Three months of strikes have been costing Qantas Aus$15 million ($16 million) per week, with the total financial impact so far hitting Aus$68 million.

The grounding of the fleet came a day after a heated annual general meeting, with Joyce being accused of running the carrier into the ground while reaping massive personal rewards.

But Joyce on Sunday said the union's reaction to decisions taken at the meeting had been the catalyst that forced Qantas to take the drastic step of grounding flights.

One union leader had warned that protests could stretch until mid-2012 while ground staff leader Tony Sheldon threatened crippling 48-hour strikes.

"They weren't listening to the shareholders and then they talked about escalating the dispute. That was the threshold moment that changed everything, and it was only after the AGM we saw that."

He denied union claims that Qantas had been planning the shutdown for some time, saying all airlines have shutdown contingencies to cope with various crises.

Passengers were stranded at all Australian airports as well as in Qantas hubs such as Hong Kong, Singapore, London, Frankfurt and Los Angeles.