Vietnamese authorities prevented Jetstar Pacific chief operating officer Daniela Marsilli and chief financial officer Tristan Freeman from returning to Australian on December 19 over allegations that the company made huge losses on fuel markets.
Alan Joyce, chief executive of Qantas, which part owns Jetstar, admitted that losses from so-called fuel hedging ran into hundreds of millions of dollars but said the practice of fuel hedging was routine within the airline industry.
He added that he was confident the employees had done nothing wrong.
"The losses that were incurred were a part of global business risk," Mr Joyce told reporters in Sydney on Saturday.
He added that the two employees had not acted outside the company board structure.
"We'll do whatever is necessary to ensure a speedy resolution."
Ms Marsilli and Mr Freeman have been prevented from leaving Vietnam while authorities there undertake a financial investigation.
The Vietnamese government is a shareholder in the budget airline Jetstar Pacific.
According to international media reports, the former boss of Jetstar Pacific, Luong Hoai Nam, was arrested on Thursday as part of the investigation into the 2008-09 losses.
Vietnam's Tuoi Tre newspaper quoted a report by state investigators that the three Jetstar employees flouted a board of directors' resolution on buying aviation fuel futures, leading to losses of more than $US31 million ($A33.81 million).
In 2007, Australia's Qantas bought 18 per cent of Pacific Airlines and turned it into a low-cost airline operating as Jetstar Pacific. Qantas's stake has since increased to 27 per cent.
