South Africa lock Flip van der Merwe will miss the Rugby Championship decider against New Zealand on Saturday after he was suspended for one week for striking an opponent.

SANZAR, the southern hemisphere's rugby authority, held a judicial hearing and found Van der Merwe guilty of striking Australian winger Joe Tomane with his forearm as he attempted to make a tackle in the Springboks' 28-8 victory at Newlands in Cape Town on Saturday.

Van der Merwe was sin-binned for the incident by French referee Jerome Garces.

The lock denied that the blow was intentional and was handed the minimum sanction in account of his previous good disciplinary record, and the fact he showed concern towards the player at the time of the incident.

South Africa must beat the All Blacks by more than seven points and score at least four tries at Ellis Park if they are to win the Rugby Championship this season.