Qantas is the latest airline to question the credibility of Covid-19 test processing in India.
Qantas says it is reviewing the operations of its service provider in India after nearly half of the passengers were barred from taking the first repatriation flight out of India after testing positive.
The first flight landed in Darwin at the weekend with just 80 of the 150 scheduled passengers.
Forty-two passengers tested positive in a second pre-departure test and another 31 of their close contacts were barred from travel.
Qantas added a second layer of protection which identified the positive cases with a rapid antigen test taken after a standard PCR test.
All passengers required a mandatory three-day hotel stay in Delhi prior to travel.
With so many positive cases flagged, Qantas is reviewing the company in charge of processing the test results.
"If there are concerns we will work together with the Department of Foreign Affairs and Trade to ensure the process is working as it should," Qantas said.
"The reason we went to India was to bring home as many Australians as possible. Together with DFAT all the protocols put in place were designed to minimise the risk of importing the virus and maximise the safety of everyone on board."
A DFAT spokesperson said: "The introduction of the rapid antigen testing in addition to the PCR testing, as well as the strict protocols introduced by the hotel, added an additional layer of assurance."
Qantas said the testing lab in India was accredited despite reports the National Accreditation Board for Testing and Calibration Laboratories blacklisted CRL Diagnostics last month.
The quality of Covid test processing at India labs has been called into question for months with numerous instances of passengers testing positive on arrival overseas despite having negative test results.
