Siriwardana, Rajitha included for Australia T20Is
Along with Rajitha and Siriwardana, Sri Lanka have also named off-spinner Sachithra Senanayake and batsman Chamara Kapugedara in the side.
Missing out on selection are Niroshan Dickwella, Farveez Maharoof, Lahiru Thirimanne and Danushka Gunathilaka along with Angelo Mathews and Nuwan Pradeep, who are injured.
In the absence of Mathews, who is suffering from a calf tear, Sri Lanka will be led by Dinesh Chandimal, who also captained the team in the fifth and final One-Day International in Pallekele.
While Senanayake is the specialist spinner in the squad, Sri Lanka have abundant all-rounders like Dhananjaya de Silva, Seekkuge Prasanna, Siriwardana and Sachith Pathirana.
The two games in the series will be played on Tuesday and Friday and it will be the final international outing for Tillakaratne Dilshan, who has recently announced his retirement.
Sri Lanka T20 squad: Dinesh Chandimal (capt), Tillakaratne Dilshan, Kusal Perera, Dhananjaya de Silva, Chamara Kapugedara, Milinda Siriwardana, Kusal Mendis, Seekkuge Prasanna, Sachithra Senanayake, Suranga Lakmal, Thisara Perera, Sachith Pathirana, Kasun Rajitha, Dasun Shanaka.
© Cricket World 2016