Dominating the second session of the encounter, the Kiwi side ran over the Argentina defence after the two teams were 2-2 level until the 57th minute.
This victory gives New Zealand the maximum six points from two outings, having outplayed five-time champions India 5-1 in the first outing yesterday.
Argentina, the Pan-American champions, have lost both their matches, after suffering a 2-4 defeat at the hands of Pakistan in the first match.
Great Britain, the highest ranked team in the tournament, seemed set to take full points from their first outing until Saari scored two outstanding field goals in the 67th and 68th minutes to the delight of the spectators.
This draw gives Malaysia two points from as many games, after having held South Korea to a 1-1 draw yesterday.
Great Britain opened the scoring in the fifth minute through Glenn Kirkman, only to see Azlan Misron draw parity for Malaysia in the 10th minute.
Strikes from Ashley Jackson (20th minute) and Rob Moore (35th) gave Great Britain a 3-1 lead at the interval and were on course until Saari's two late goals. More
