Fly-half Morne Steyn and fullback Zane Kirchner have kept their places despite criticism after the team's poor away run comprising defeats by New Zealand and Australia and a draw with tournament newcomers Argentina.
Meyer has however increased his options in both positions by calling up number 10 Elton Jantjies and number 15 Jaco Taute, who are both uncapped, for the September 30 match with the Wallabies and the October 7 encounter with the All Blacks.
"I'd always wanted to include Jaco in the squad but an untimely injury meant we could not select him earlier," Meyer said in a statement.
"Jaco is big, strong, fast and versatile and it will be good to get him involved," he said of the 21-year-old.
Prop CJ van der Linde, who last appeared for the Springboks against Namibia at the World Cup a year ago, was picked along with Coenie Oosthuizen who has played 35 minutes of Currie Cup rugby for the Cheetahs after injuring his neck against England on June 9.
Van der Linde and Oosthuizen were included because tighthead props Jannie du Plessis and Pat Cilliers are carrying injuries and Dean Greyling is suspended.
Meyer is under pressure from the fans to drop Steyn, who succeeded with only one of his five kicks at goal in the 21-11 defeat by the All Blacks in Dunedin last weekend, for Jantjies or Johan Goosen.
South Africa have to beat Australia and New Zealand with a bonus point, while hoping the All Blacks lose in Argentina, to have any chance of winning the inaugural Rugby Championship title.
"There were a number of positives we took from the matches in Perth and Dunedin and it is imperative we build on those," said Meyer.
"Australia and New Zealand won't be easy. The All Blacks are unbeaten this year and the Wallabies have done well to win their last two matches so we will have to be at our best at Loftus Versfeld and Soccer City."
Squad: Pat Lambie, Zane Kirchner, Bryan Habana, Jean de Villiers, Juan de Jongh, Francois Steyn, Jaco Taute, Francois Hougaard, Lwazi Mvovo, Johan Goosen, Elton Jantjies, Morne Steyn, Ruan Pienaar, Duane Vermeulen, Willem Alberts, Jacques Potgieter, Francois Louw, Marcell Coetzee, Juandre Kruger, Andries Bekker, Flip van der Merwe, Eben Etzebeth, Jannie du Plessis, Pat Cilliers, Adriaan Strauss, Tiaan Liebenberg, Craig Burden, Tendai Mtawarira, CJ van der Linde, Coenie Oosthuizen