Foster said the rivalry with the Springboks was already intense but would only be increased after the performance of the South Africans over the past couple of matches.
"South Africa is coming off a draw and a loss. It is really important for them to get a win.
"We have the South African rivalry, which is legendary. We know it is going to be a very tough battle for us. We are going to have to front up physically, like we did last week," Foster said.
Foster said playing a second tough side in a row, after the Argentinians last week, would mean the side would have to show plenty of commitment, though the South Africans would bring some new options to the table.
"They offer a couple of different things. Those high balls they pump in, that whole aspect of the game is very important.
"You just have to focus on collisions and you know they are going to come at you 100 miles an hour. It is about body position, where you go in attack, find the weak seams, and individuals taking responsibility to put their work in."
The All Blacks have been slowly working into their game in the Rugby Championship and though they are unbeaten in their first three games they are yet to put in a polished performance.
"We have not quite got the finishing right yet. Last week in particular, in the last 30 minutes anyway, I think we were getting things right. It is going to be a pacy and very aggressive test match this week.
"The first 40 minutes last week the conditions were terrible and that probably forced us into making a few decisions that we should not have made.
"But in that second half I was really pleased the way the nine and 10, in particular, stepped into making the decision-making."
Foster said the side had come through well from the Argentinian test and all but Dan Carter were likely to be available for Saturday night's test.
After being soaked and blown away last Saturday night in Wellington, the side was looking forward to getting under cover at the Forsyth Barr Stadium.
Foster said the covered stadium meant there could be assurance about what sort of game plan the side would look to play.
"Frankly, the team is very excited to be playing in this stadium. We have watched a lot of Super rugby in this stadium and we can't wait."
