Morkel last played for the Proteas in a T20 international in October 2012, but following a strong performance for the Titans in Domestic T20 competition was recalled to the team.
Hendrick, meanwhile, was the new cap in the Proteas side to be captained by Faf du Plessis.
South Africa’s first T20 assignment will be a three match series against the touring Australians in March, before the side jet off to the subcontinent for the World T20 tournament.
Proteas convenor of selectors Andrew Hudson said it was a straight-forward decision to include Morkel in the squad.
“From an experience point of view, we all know what Albie has done around the world,” Hudson said at OR Tambo International Airport on Monday.
“He’s also played in the subcontinent and done well. His recent form has made it easy for us to include him in the squad.
“To finish games, perhaps to be behind David Miller gives us a nice option at seven. I think it strengthens the team hugely.”
Hudson said Hendricks would be valuable to keep things tight at the end of the innings.
“Hendricks’ inclusion underlines that guys doing well domestically can get a real look in,” he said.
“He’s got good death bowling skills. It’s also nice to have a number of good combinations in the side.”
The women’s squad for their T20 World Cup in Bangladesh in March was also announced on Monday, and captain Mignon du Preez was pleased with the blend of players at her disposal.
“I’m very happy with the side, there’s plenty experience and youngsters in the side with good talent,” said Du Preez.
“We just had a successful tour of Bangladesh, and our main goal to get to the semi-finals of the competition.”
Men’s Squad: Faf du Plessis (capt), Hashim Amla, Farhaan Behardien, Quinton de Kock, AB de Villiers, JP Duminy, Beuran Hendricks, Imran Tahir, David Miller, Albie Morkel, Morne Morkel, Wayne Parnell, Aaron Phangiso, Dale Steyn, Lonwabo Tsotsobe.
Women’s Squad: Mignon du Preez (capt), Trisha Chetty, Moseline Daniels, Shandre Fritz, Shabnim Ismail, Marizanne Kapp, Lizelle Lee, Marcia Letsoalo, Sunette Loubser, Sune Luus, Nadine Moodley, Chloe Tryon, Yolandi van der Westhuizen, Dane van Niekerk. Non-traveling reserves: Yolani Fourie, Ayabonga Khaka, Yolandi Potgieter.