The fierce competition for places in the match day squad is driving the South Africa to new heights, according to captain Siya Kolisi, as his side prepare to face old foes New Zealand in a Rugby Championship Test at Ellis Park on Saturday.

The Springboks, victorious twice in Australia in August, have won the last two Rugby World Cup titles and are seeking a third victory in a row against the All Blacks for the first time since 2009.

It is hard to think of a time, certainly since the country's readmission to international rugby in 1992, when the national team have had such depth across the board.

And with coach Rassie Erasmus not afraid to make changes if he feels even his established names are not hitting the standards they should, it means the pressure to perform is always there.

"When you put on the Springbok jersey, there is a lot to play for," Kolisi told reporters on Friday. "The competition is not the opposition; it is the guys who you are playing with. But it is healthy competition.

"Within the group we help each other. (Fellow flanker) Marco (van Staden) is my best coach, Kwagga (Smith) is my best coach.

"You can not relax in a Springbok jersey. You can never be comfortable, because someone is coming for you. We are blessed with loose forwards in South Africa, we have so many."

New Zealand are the Springboks' fiercest rivals and with the memories of last year's World Cup final, where the South Africa edged the contest 12-11 in Paris still fresh in the mind, Kolisi expects the All Blacks to be fired up.

But as they chase a rare Rugby Championship title, keeping the feel good factor in the country around the Springboks is also important.

"People talk about how much pressure there is in the game. But Rassie said it in 2019, we are in a place of privilege of being able to represent the whole of South Africa, not just some people," Kolisi said.

"You can control people's mood on a Monday morning (with results). We think about that, it is just different when you are putting on a Springbok jersey."

South Africa lead the Rugby Championship table after two rounds following a full haul of 10 points from bonus-point wins in Australia. New Zealand are second with five points.

There will be a second meeting between the sides in Cape Town on Sept 7.