(Reuters) - South Africa have made two changes to their forward pack for the Rugby Championship test against New Zealand on Saturday, while prop Jannie du Plessis has been given a few more days to prove his fitness ahead of the Dunedin clash.

The Springboks crumbled to a demoralising 26-19 loss against Australia in Perth last weekend and next face a Herculean task of trying to upset the undefeated All Blacks in their southern stronghold and get their tournament back on track.

Springboks coach Heyneke Meyer, who came close to destroying a walkie-talkie out of frustration during the Perth defeat, called up lock Flip van der Merwe in place of the suspended Eben Etzebeth when he named his squad on Wednesday.

Etzebeth was banned for two weeks for head-butting Wallabies lock Nathan Sharpe during Saturday's loss.

Francois Louw has been promoted from the reserves in place of Marcell Coetzee at blindside flanker, a move seemingly aimed at nullifying All Blacks captain Richie McCaw's ball-poaching at the breakdown.

"The New Zealanders are good on the ground which is why we decided to go for a specialist openside flank in Francois," Meyer said in a media release.

"Marcell has been very good this season and has played a lot of rugby, but in this match we feel he will be more useful as an impact option."

Du Plessis has been given until Friday to shake off a hamstring injury and will be replaced by Pat Cilliers if he fails to recover in time.

After a home victory over newcomers Argentina and an away draw to the same opponents on the return leg, the Springboks faded badly in the second half against the Wallabies, prompting South African media to question fitness levels.

Former Leicester coach Meyer, who succeeded the controversial Peter de Villiers after their quarter-final exit at the World Cup, has injected fresh legs onto the bench, with lock Andries Bekker, prop Dean Greyling and versatile back Juan de Jongh all called up as replacements.

New Zealand followed up back-to-back victories over the Wallabies with a bruising home win against the Pumas in Wellington last week.

Team: 15-Zane Kirchner, 14-Bryan Habana, 13-Jean de Villiers (captain), 12-Frans Steyn, 11-Francois Hougaard, 10-Morne Steyn, 9-Ruan Pienaar, 8-Duane Vermeulen, 7-Willem Alberts, 6-Francois Louw, 5-Juandre Kruger, 4-Flip van der Merwe, 3-Jannie du Plessis, 2-Adriaan Strauss, 1-Tendai Mtawarira.

Replacements: 16-Tiaan Liebenberg, 17-Dean Greyling, 18-Andries Bekker, 19-Marcell Coetzee, 20-Johan Goosen, 21-Juan de Jongh, 22-Pat Lambie

(Reoprting by Ian Ransom in Melbourne; Editing by Peter Rutherford/John O'Brien)

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