The 25-17 loss was the Springboks' second defeat in a row in the Rugby Championship and their third reversal in six matches in 2022, leaving Nienaber concerned his team's inability to convert scoring opportunities is costing them victories.

"If you look at the last test against Wales, there were three times we were over the try line and it was disallowed," Nienaber told reporters.

"Against New Zealand in the last test match we were over the try line three or four times and it was disallowed, and tonight I thought we were over the try line or close, five metres or two metres from the try line, and we didn't score.

"It's 50-50. Hats off to Australia, I thought their defence was good and we didn't capitalise. It's frustrating. We're emotional now but we will have to have a good look and see why.

"We camped out in their 22 in the back end of the first half and we just didn't get any conversion of points."

South Africa sit bottom of the four-team Rugby Championship standings after three rounds, six points behind leaders Argentina and Australia, but Nienaber is confident the reigning world champions can bounce back.

The Springboks will travel to Sydney ahead of Saturday's second meeting with Dave Rennie's side at Sydney Football Stadium.

"That's the beauty of rugby, you have seven days and then you get another opportunity," he said.

"So we'll take our lessons and have a good look at the game and change a couple of things if we have to and then it's on to the next week."