Talks between Qantas Airways and two key unions have broken down without agreement over pay and conditions.
The Transport Workers' Union and the Australian and International Pilots' Association have been in conciliation talks before Fair Work Australia since Qantas ordered its planes grounded worldwide for 48 hours on 29 October.
Qantas said it was losing $A15 million per week due to months of strikes and industrial action by the three unions.
The pilots' union says it is "bitterly disappointed" would not agree to demands it presented to the airline last Friday. It has accused Qantas of sabotaging the talks.
The unions will now go to arbitration with Qantas after the airline rejected their request for a further 21 days to negotiate.
The ABC reports that a third union, the Australian Licensed Aircraft Engineers' Association is still in talks with the airline, and has until midnight on Tuesday to reach a deal.
Earlier, Qantas spokeswoman Olivia Wirth said the company would stand by any decision made by the industrial umpire if the disputes went to arbitration.
"This is legislated in Fair Work Australia; this is the process that both parties have to agree to," she said.
"We would not be seeking any overturning of this in the Federal Court."
