The new players were not on the initial list for the 2016/2017 season announced a year ago but they have since forced their way into the selectors' plans.
Nathan Coulter-Nile, John Hastings, Peter Nevill and Peter Siddle have also been added to the 20-man list as Australia looks ahead to the home Ashes series starting in late 2017.
"There is a lot of talent within this group and we have confidence that the players chosen can be successful in all three forms of the game," chief selector Rodney Marsh said in a statement.
Michael Clarke, Brad Haddin, Ryan Harris, Mitchell Johnson, Chris Rogers and Shane Watson all called it quits for Australia last year.
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Australian media said batsman Khawaja was expected to pocket more Aus$1 million ($770,000) from his new contract after his sparkling form in all three formats.
Burns is reaping the benefits of his ascension to Test opener, replacing the retired Rogers, which included his man-of-the-match 170 against New Zealand in Christchurch in February.
The minimum value of a Cricket Australia contract for the 2016-17 season is Aus$270,000 while any player awarded an upgrade contract will earn at least Aus$230,000 ($176,000), CA said.
CA's contracted players 2016-17: George Bailey, Joe Burns, Nathan Coulter-Nile, Patrick Cummins, James Faulkner, Aaron Finch, John Hastings, Josh Hazlewood, Usman Khawaja, Nathan Lyon, Mitchell Marsh, Shaun Marsh, Glenn Maxwell, Peter Nevill, James Pattinson, Adam Voges, Peter Siddle, Steve Smith, Mitchell Starc, David Warner.