In his opening address to a Senate inquiry on Tuesday night, Mr Joyce said unions were running a line that the prospect of repealing a key part of the Qantas Sale Act would adversely affect safety.

''This is blatant fearmongering. It is playing the safety card as a tool of industrial relations,'' he told the Senate economic legislative committee.

In a bid to stop the government from relaxing the Qantas Sale Act, the Australian Licensed Aircraft Engineers Association last week released to a separate Senate inquiry a dossier detailing errors on Qantas planes following maintenance in Singapore, Hong Kong and Kuala Lumpur.

But Mr Joyce told senators on Tuesday night that they needed ''no reminder of the absolute Qantas commitment to safety'', emphasising that maintenance on its planes was approved by the Civil Aviation Safety Authority and done to the airline's high standards regardless of where it was carried out.

''As always in aviation, there are multiple fail-safes to account for the very small likelihood of human error,'' he said. ''Suggesting that any mistake is a potential catastrophe is alarmist and deeply irresponsible.''

The engineers' union has also accused CASA of giving Qantas ''preferential treatment''.

The senators are weighing up the impact on the aviation industry and the broader economy of a relaxation of the Qantas Sale Act, which caps foreign ownership in the airline at 49 per cent.

Ahead of the hearing, the ACTU's national executive passed a resolution that condemned Qantas' decision to cut 5000 jobs, seek a wage freeze from employees, and to send more jobs offshore. The resolution also called on the government not to remove provisions in the Sale Act that keep the majority of Qantas jobs in Australia.

ACTU secretary Dave Oliver said the airline still had not explained why 5000 jobs must go or where and when they would be cut, despite two meetings with Mr Joyce.

''Qantas workers are turning up to work every day not knowing if their jobs are safe. This is no way to treat workers,'' he said. ''It is unfair that Qantas workers are paying the price for poor management decisions and a federal government that is out to cut jobs and wages.''

Earlier, Liberal senator Ian Macdonald told the Coalition's party-room meeting that independent senator Nick Xenophon and Labor senator Sue Lines had helped the government prosecute its argument for changes to the Qantas Sale Act during a Senate hearing last Friday.

Senator Macdonald told the meeting the ALP's characterisation of anything connected to outsourcing airline jobs to Asia as a bad thing during the hearing was ''revisiting the White Australia Policy''.

Prime Minister Tony Abbott agreed with Senator Macdonald's sentiments and added the ALP's campaign against the 457 visa program for skilled workers, which began under former prime minister Julia Gillard, showed ''the ALP just doesn't get modern Australia''.