The world No 4 Black Sticks began strongly and maintained their intensity to the finish. Australia were unable to break the defence.
Pint-sized dynamo Punt scored the opening goal with a rasping shot from a penalty corner, and laid on the pass for the crucial second goal by midfielder Ella Gunson.
Punt's goal enabled her to overtake Katie Glynn and Krystal Forgesson as the country's alltime leading goalscorer with 78.
Along with Michelsen in harness down the right-hand attacking channel, the pair were a constant threat with their pace and ball control.
"Anita and I have played on the right side for a long time now so we do work really well together," Michelsen said.
"It's good when I can recognise her pace and get the ball to her, and going forward it's really important we do get those combinations going."
Michelsen pointed to Punt's importance at the set piece penalty corners.
New Zealand had a dismal record at the tournament before Punt struck just after halftime yesterday, having converted none from 12 opportunities to that point.
"It's a really important part of our game to try and get Anita into attack and scoring goals and also with her penalty corner flicking."
Next up they face hosts Belgium to finalise the quarter-final placings.
New Zealand will be aware their men's counterparts slipped up in their equivalent tournament in Buenos Aires this month at a late stage and against much lower-ranked opposition.
The result of their losses to Canada and Spain meant they failed to secure an automatic spot in the field for the Rio Olympics. They can still get there, but they've made it harder for themselves.
The women's team are determined not to get foot-tripped from this point.
"We're definitely aware that we can qualify for Rio. Every team wants to qualify because you don't want to leave it till a later date.
"But we just take each day as it comes and concentrate on the team on the day, not look beyond that and get ahead of ourselves," Michelsen added.
The Belgians are ranked No 12 but Michelsen said they impressed against Australia and there won't be any risk of taking the challenge lightly.
New Zealand have a considerable weapon in their pace across the field.
They have defenders who tackle well and have the speed to recover if they get in trouble and, as Australia discovered, can put the wind up opposing defensive units with their ability to break fast.
"It's the first time we have managed to open up Australia that much in a long time - we stuck to the game plan and moved the ball well," coach Mark Hager said.
What happens next
New Zealand play hosts Belgium in their final pool B game early tomorrow (NZT). They then have a quarter-final against, most likely, Korea or Japan, next Tuesday.
Their 2-0 win over Australia yesterday was just their 17th in 112 internationals against the world No 2 Aussies.
The top three teams at the world league semifinal qualify automatically for next year's Rio Olympics. Make the top four and they advance to the World League final at the end of the year.
