Just one traveller who returned to Australia on board a repatriation flight from India has tested positive for coronavirus.
But the number of positive cases could rise as other passengers who landed in Darwin on Saturday undergo further tests.
The infected passenger has been placed in isolation at the Howard Springs quarantine site.
"I have news this morning that probably only one - they're still subject to further testing - but only one person has tested positive in that group," Northern Territory acting chief health officer Charles Pain said on Monday.
"So the testing that was done in India has clearly been effective and has had the effect that we intended, which was that people wouldn't come on the flights if they were positive."
The flight was the first to land in Australia from India since the federal government implemented a travel ban and tighter pre-departure restrictions several weeks ago.
Passengers booked on the charter flight were required to return two negative tests before boarding.
About half of the 150 passengers were turned away after testing positive or being deemed close contacts of positive cases.
Some of those left behind in New Delhi have urged Australian authorities to reconsider their screening processes, given at least three passengers have since tested negative to coronavirus.
Health Minister Greg Hunt defended Qantas' testing processes as "strong and rigorous".
"It's very important to understand that somebody might test negative during the incubation period and then become positive," he told reporters in Melbourne.
"Equally, somebody may test positive and then subsequently become negative as they clear the virus."
Mr Hunt rejected suggestions of allowing people to return from India while positive, describing such a move as "dangerous and irresponsible in the extreme".
Dr Pain acknowledged being blocked must be "desperately disappointing" but said health officials were working to get those who tested positive onto future charter flights.
"It's expected that they will re-join the testing queue, or the queue to get on those flights, as soon as possible," he said.
"It's expected that some of those people who tested positive will return negative tests (next time)."
India has recorded an average of 340,000 coronavirus cases during the past seven days, with about 4000 deaths recorded each day.
Australian Associated Press