Qantas and aircraft engineers have exchanged more blows over the quality of maintenance conducted overseas.

Lawyers for Qantas have launched a detailed rebuttal of claims by aircraft engineers that maintenance done outside of Australia is unsafe.

The airline has provided a six-page response to union allegations made to a Senate committee, which will report next week on an inquiry into Qantas jobs.

It will be one of two reports presented to parliament on Qantas – the other being an inquiry into proposed law changes which would allow the airline to take on majority foreign ownership.

The Australian Licensed Aircraft Engineers Association told the Qantas jobs inquiry there had been serious problems with maintenance conducted offshore between 2003 and 2007.

Among the allegations were the incorrect installation of three engines during a Boeing 747 offshore check in 2008, wrong tools and parts being used on a number of occasions and poor oversight of work.

The union said up to 600 mistakes had been made on one aircraft alone.

But the airline’s general counsel Andrew Finch told the inquiry the claims were “sensationalist and scaremongering”.

“Seen in their best light, the claims identify that a series of predominantly minor servicing issues were identified and remedied according to Qantas’ multiple failsafe mechanisms, reported to the Civil Aviation Safety Authority (CASA) and appropriately recorded and discharged.”

The union was “cloaking an industrial agenda in alleged safety issues”, the airline said.

Qantas said most of its maintenance was done at its Brisbane facility.

But its fleet of A380s and B747s are maintained in the Philippines and Hong Kong.

“Regardless of geography, all our maintenance is done at facilities approved by CASA and to Qantas’ high standards,” the airline said.

The union said in a statement provided to the inquiry that there was clear evidence of mistakes being made in offshore facilities.

ALAEA federal secretary Steve Purvinas said there were also examples of Qantas’ audit teams finding problems that CASA checks did not identify.

“They have provided no evidence, broadly reject claims as being scaremongering and often fall back on CASA as the supporting authority who have approved particular facilities or actions,” he said.

“We don’t consider (CASA) approval of any facility or work practices a true or tested measure of safety.”

Labor and the Greens have voiced their opposition to allowing majority foreign ownership of Qantas, saying jobs would be shipped offshore and safety standards would fall.

But Prime Minister Tony Abbott said the changes would allow the airline to take on extra capital and compete on a level-playing field with other carriers.