Australian Prime Minister Julia Gillard on Thursday urged national carrier Qantas to resolve its dispute with unions, as the airline\'s chief warned that further strikes could cost jobs. Qantas has grounded seven jets and axed almost 500 flights over the next month due to a maintenance backlog following go-slows and stop-work actions from its engineers over stalled contract talks. The airline is also facing rolling strikes by ground staff that have seen some 550 flights cancelled or rescheduled since August, while pilots are also waging a low-level, largely symbolic campaign. Gillard said she was \"concerned\" about the dispute. \"My message remains to the parties: get around a table and get this fixed,\" the prime minister told reporters. \"The parties themselves need to come together, negotiate and get this done.\" Staff unions are angry about Qantas plans to restructure its international business towards Asia, which will see 1,000 jobs axed, and they want guarantees on wages and job security. Qantas chief Alan Joyce warned that further aircraft could be grounded and the jobs of \"innocent bystanders\" could be at stake. \"If we have to keep grounding aircraft due to the ongoing industrial action then there will be jobs at risk within the rest of Qantas,\" Joyce told News Limited newspapers. \"Cabin crew, airport staff and short-haul pilots, these are some of the innocent bystanders in this dispute.\" Engineers offered a truce Thursday, calling off all industrial action for three weeks as a challenge to Qantas claims that aircraft groundings were directly linked to their strike. \"We believe that Qantas have falsely stated that aircraft have been grounded due to protected industrial action when we believe that is not the case,\" said Steve Purvinas, head of the engineers\' union. \"We challenge Qantas to use as much overtime and work from our members as possible to get those aircraft back into the air.\" Tens of thousands of passengers have been affected by the strikes, raising the prospect of government intervention, which is triggered if the Australian economy or the welfare of its population is deemed to to be under threat. Conciliation talks are continuing between Qantas and engineering representatives, and a meeting with pilots is due next Friday. But ground staff in Brisbane and Melbourne are set to walk off the job for one hour on Tuesday morning after negotiations with Transport Workers\' Union delegates again failed.