Erasmus issues warning for surging Boks ahead of All Blacks rematch

Coach Rassie Erasmus said the All Blacks will be a "step up" in competition after South Africa swept past Australia to kick-start their Rugby Championship campaign in style.

The two-time reigning world champions scored the game's only four tries in their 30-12 victory in front of 58 197 fans at Perth's Optus Stadium on Saturday.

South Africa made 10 changes after a 33-7 triumph last week in Brisbane, but their depth of talent and firepower off the bench crushed a gritty Wallabies in wet conditions.

"We have always struggled against Australia," said Erasmus as South Africa won four straight matches against the Wallabies for the first time since their readmission to international rugby in 1992.

"We are always pleased with a win, and to get two bonus-point wins over here and the fact that all 33 players on tour played was fantastic.

"There were a few more tries that we could have scored, so it could have been a bigger winning margin, but we are pleased with earning five points two weeks in a row."

Heavy rain lashed the ground as several players were forced off with head injuries amid a ferocious contest.

Australia suffered the brunt of the casualties, but South Africa did lose stand-in captain Salmaan Moerat early in the game after he copped a knee to his head.

"(Moerat) will go through (concussion) protocols... we do have a week off, so don't foresee him missing the next game," Erasmus said.

The Springboks will next host two tests against a rejuvenated All Blacks, starting with a clash in Johannesburg on August 31.

It will be the first time the powerhouses meet since last year's tense World Cup final when South Africa defended their title with a 12-11 victory.

NEW ZEALAND BACK IN FORM

After a shock loss to Argentina in Wellington last week, New Zealand exacted revenge and returned to form on Saturday with a 42-10 thumping win at their Eden Park fortress.

"We saw how New Zealand turned things around after last week's result, so we know the challenge that awaits us...it will certainly require another step up," said Erasmus.

"With all due respect to Australia, they are in a rebuilding phase and (new coach) Joe Schmidt is also still finding his feet, so the next two tests will be tougher.

"We are facing them at altitude in Johannesburg and then in Cape Town where they enjoy playing, so we are excited about what will be almost a mini-series against them."

Meanwhile, Australia counted the cost from a gruelling clash after their front row was decimated by head injuries to captain Allan Alaalatoa, Angus Bell and James Slipper.

Inside centre Hunter Paisami and hooker Josh Nasser also suffered leg injuries.

"I've been involved in coaching over 100 test matches and I've never seen that (injuries in quick succession) before," said Schmidt, whose record as Australia coach fell to 3-2.

The winless Wallabies face the tough task of travelling to Argentina for back-to-back matches.

"It doesn't get easier going to Argentina next," Schmidt said.

"They'll be disappointed with their first-half (against New Zealand), but they demonstrated how tough they can be to beat when they toppled the All Blacks.

"They won't be taking it easy on us, and we'll try to make it difficult for them."