Measures include masks on board, hand-sanitising stations and enhanced aircraft cleaning, as well as more flexibility with booking cancellations.

Contactless check-in, self-service bag drops and hand-sanitising stations at departure gates will also be in place under the airline's Fly Well program which launches on June 12.

In addition, the air-conditioning systems of all Qantas and Jetstar aircraft are already fitted with hospital-grade HEPA filters, which remove 99.9 per cent of all particles including viruses.

Deputy Chief Medical Officer Paul Kelly says discussions had been going on since January and had now concluded, with Qantas making its own risk assessment and decisions.

"They've made that risk assessment and they've mitigated as much as they can," Professor Kelly said on Wednesday.

He said masks had not been recommended by medical experts but were included in the measures in any case.

"We didn't specifically say they should include masks but that's one of the ways they've looked at how they can decrease the risk whilst also looking to have a viable industry and to be able to fly," he said.

Ventilation on the aircraft was "safer than a closed room", but "probably not as safe as an outdoor cafe", he said.

"But, look, we live in a very big country. We do need our aircraft to get around ... and we do want our airline industry back on their feet," he said.

Prof Kelly said passengers should ensure they don't travel if they are sick.

The Fly Well program is due to be reviewed after one month.

Although Qantas chief executive Alan Joyce says the carrier has experienced "no person-to-person known transmission on an aircraft" since the COVID-19 crisis began, the Transport Workers Union says the airline can't be trusted when it comes to tackling the coronavirus.

TWU national assistant secretary Nick McIntosh on Wednesday rejected Qantas' program as insufficient.

"Qantas (is) simply not consulting their workforce ... and can't be trusted when it comes to the coronavirus," he told reporters in Sydney.

Mr McIntosh called on the federal government to enact a national plan that dealt with both safety and economic issues facing the aviation industry.

"Airlines doing their own thing will always mean they put profit over people," Mr McIntosh said.

Mr Joyce on Wednesday defended the airline's decision not to abide by social distancing on flights, insisting it would be uneconomical to leave the middle seat in every row vacant.

"That's not social distancing, it's a 60-centimetre difference between two people," Mr Joyce told ABC radio.

"To get the four metres squared (per person) you'll end up with 22 people on an aircraft of 180 seats and the airfares are nine to 10 times as much."

Australian Associated Press