Jetstar is offering 10,000 one-way fares for $19 on 22 routes, including Melbourne to Sydney, Sydney to Gold Coast, Melbourne to Ballina, Brisbane to Whitsunday Coast and Adelaide to Cairns.
Other routes have also been discounted but not to the same extent.
Qantas is offering triple points for frequent flyers on all routes as part of a plan to reboot domestic air travel.
Customers of both airlines will also be given more flexibility to change flight dates without being hit with fees.
Qantas Group chief executive Alan Joyce says almost 400,000 seats have been sold on Qantas and Jetstar’s domestic networks in the past two weeks, after some state borders opened.
He hopes the sale and points offers will boost that further and help tourism operators get back on their feet.
Qantas and Jetstar will continue to reintroduce flights across its domestic network in line with demand and the easing of border restrictions.