Australian Prime Minister Julia Gillard has called for an end to industrial action which has seen Qantas ground all its international and domestic flights.Qantas said 68,000 passengers were affected by its grounding of 108 aircraft in 22 cities worldwide.The airline announced it would also lock out staff involved in industrial action, after months of strikes.But the pilots union has threatened legal action against the move.Ms Gillard said the government had applied to regulator Fair Work Australia, \"the industrial umpire\", to try to get planes back in the air.The prime minister said she was concerned about damage that could be caused to the national economy.\"I believe Australians want to see this dispute settled. I want to see this dispute settled and we have taken the appropriate action to bring this before the industrial umpire,\" she told a news conference from the Commonwealth Heads of Government meeting (Chogm) being held in the western Australian city of Perth.Among the stranded passengers are 17 world leaders attending the Commonwealth summit in Perth. Ms Gillard said they had found alternative flights.Fair Work Australia reconvened an emergency panel at 1400 (0300 GMT) on Sunday, after an earlier hearing was adjourned in the early hours of the morning.The tribunal can decide whether to order an end to industrial action by both unions and management.Qantas chief executive Alan Joyce said his planes could be in the air again by late Sunday if the panel ordered a termination of all industrial action, but he warned an order to simply suspend it - as the unions were seeking - would not be good enough.The airline - the world\'s 10th largest - has been hit by a series of costly strikes and other industrial action, which the company said was costing A$15m ($16m) a week.Pilots have been engaged in protracted talks with management over wages, conditions and outsourcing of jobs to Asia, but they have yet to walk off the job - unlike baggage handlers, engineers and ground staff.Australian International Pilots Association (AIPA) vice-president Captain Richard Woodward said work stoppages were not in their plans.\"Pilots have made it clear from the start that we would not take industrial action that disrupts passengers. We have stuck to that to this day,\" he said.\"Alan Joyce, on the other hand, has opted to disrupt passengers in the most devastating way possible.\"Pilots have not been on strike and we are not seeking anything that would damage profitability.\"Mr Woodward described Qantas\'s action as \"a cynical act of insanity\".A statement by Qantas said all employees involved in industrial action would be locked out from Monday evening and flights grounded from 0600 GMT on Saturday.Aircraft currently in the air would complete their flights, but there would be no further departures.Qantas chief executive Alan Joyce said his planes could be in the air again by late Sunday if the panel ordered a termination of all industrial action, but he warned an order to simply suspend it - as the unions were seeking - would not be good enough.The airline - the world\'s 10th largest - has been hit by a series of costly strikes and other industrial action, which the company said was costing A$15m ($16m) a week.Pilots have been engaged in protracted talks with management over wages, conditions and outsourcing of jobs to Asia, but they have yet to walk off the job - unlike baggage handlers, engineers and ground staff.Australian International Pilots Association (AIPA) vice-president Captain Richard Woodward said work stoppages were not in their plans.\"Pilots have made it clear from the start that we would not take industrial action that disrupts passengers. We have stuck to that to this day,\" he said.\"Alan Joyce, on the other hand, has opted to disrupt passengers in the most devastating way possible.\"Pilots have not been on strike and we are not seeking anything that would damage profitability.\"Mr Woodward described Qantas\'s action as \"a cynical act of insanity\".A statement by Qantas said all employees involved in industrial action would be locked out from Monday evening and flights grounded from 0600 GMT on Saturday.Aircraft currently in the air would complete their flights, but there would be no further departures.