Argentina beat Australia 25-6 in their opening game, while New Zealand and South Africa played out a 13-13 draw in torrential rain.
New Zealand Head Coach Jonno Gibbes is expecting a tough forward battle.
The Argentina pack's size is typical of teams from that country, and Gibbes said their pack was bigger than the South Africans New Zealand faced in their first game.
"Their forward play is excellent, they are very well drilled."
That was why they made only two changes in the pack, with lock Cam Christie and flanker Matt Lowe coming into the side to add some fresh legs.
"Our selection up front was a bit of continuity so that we can win the set piece battles."
That became more important after their draw. Now, there was a chance the tournament could be decided by points differentials.
New Zealand's attitude against South Africa was to win; there was no thought about the tournament overall.
That outcome approach would continue against Argentina.
"We need to get past these guys and then we can turn our attention to Australia, and what we need to get right to put ourselves in that position to win the trophy. We would like to put our names on it first if possible."
Gibbes said the draw against South Africa provided a mix of emotions afterwards.
"We were proud of the effort. We lost control of the game in the second half but then fought back and put ourselves in a position to win.
"A draw was a disappointing result in the context of the conditions.
"It was our first game, and that period just after halftime was where we let is slip a little bit."
Gibbes said the composure of the New Zealand side impressed those at the game.
"They got into a sticky situation but had the composure in terrible conditions to back themselves with the ball. Two of our four tries started from deep in our territory.
"So, these young men showed a lot of courage to back their skills, play with the ball in those conditions, and it was great to show them how that was rewarded with the two tries we scored."
Gibbes said Assistant Coach Brad Cooper was leading the attack. He has instilled confidence and is attempting to develop the players' skills to exploit space and use the ball. The two attacking tries were courageous and a result of that work.
Seven changes have been made for the game against Argentina, which allows all squad members to have time in the first two games.
Gibbes said it was important for the coaches to get to know the players on and off the field.
The selection was a mix of rewarding players and based on observations at training last week.
"We work hard on trying to understand each individual, how we can get the best out of the them but we get a fair measure of them when we see them in the game."