Australian national carrier Qantas Airways grounded its global fleet indefinitely today in a lockout of workers whose strikes have disrupted operations for weeks.

Flights in the air were continuing to their destinations and booked passengers were being rescheduled at Qantas's expense, chief executive Alan Joyce said.

Bookings had already collapsed after unions warned travellers to travel with other airlines over the busy Christmas-New Year period, and Mr Joyce told a news conference in Sydney that the unions' actions have caused a crisis for Qantas.

"They are trashing our strategy and our brand," he said. "They are deliberately destabilising the company and there is no end in sight."

Transport Minister Anthony Albanese said the government would apply to an arbitration court to rule on the strike action and the airline's response.

"The government is extremely concerned about the future of Qantas, its workforce but also the travelling public," he told reporters.

All 108 aircraft in as many as 22 countries will be grounded until unions representing pilots, mechanics, baggage handlers and caterers reach agreements with Qantas over pay and conditions, Mr Joyce said.

"We are locking out until the unions withdraw their extreme claim and reach agreement with us," he went on, referring to shutting staff out of their work stations.

"This is a crisis for Qantas. If the action continues as the unions have promised, we will have no choice but to close down Qantas part by part."

Staff will not be required to show up at work and will not be paid from Monday, Mr Joyce added.

He estimated the grounding will cost the airline 20 million dollars (£13 million) a day. It has already had been forced to reduce and reschedule flights for weeks because of a series of strikes and overtime work bans over staff concerns that their jobs are being moved overseas.

Steve Purvinas, federal secretary of the mechanics' union, the Australian Licensed Aircraft Engineers Association, described the grounding as "an extreme measure".

The recent strike action has most severely affected Qantas domestic flights.

In mid-October, Qantas grounded five jets and reduced domestic flights by almost 100 a week because aircraft mechanics had cut the hours they were prepared to work.

Qantas infuriated unions in August when it said it would improve its loss-making overseas business by creating an Asia-based airline with its own name and brand.

The five-year restructuring plan will cost 1,000 of Qantas's 35,000 jobs.