The defending world champions scored as early as the second minute when Bryson Goodwin crossed for a simple try and were relentless as they raced to a 40-0 lead by halftime.
At one stage it looked like they might threaten the World Cup record when Australia beat Russia 110-4 in 2000 or at least the Kiwis' 84-10 win over the Cook Islands in 2000, but they lost their way in the second half as they lost fluency and rhythm and won the second period only 16-10.
It was a disappointing end to what had been a phenomenally good start but it's often difficult to maintain standards when a game has already been won.
Sonny Bill Williams illustrated his class. By halftime he had a hat-trick of tries - although he nearly botched another one like he did against Samoa getting dangerously close to the dead-ball line - as well as 13 tackle breaks, four linebreaks, seven offloads, one try assist and 199m in 14 runs.
It was what the capacity crowd had come to see, although they might have also enjoyed a closer contest.
Papua New Guinea were poor in the opening period, going into the match already out of contention for a spot in the quarter-finals, but the Kiwis rarely lifted their foot off the pedal. They scored some nice tries, and Roger Tuivasa-Sheck showed his dancing feet as he scored a double, but they did the simple things well - the things that win World Cups - completing 95 per cent of their sets in the first half.
Their first mistake was when Shaun Johnson hit the upright with a conversion attempt on the half hour from right in front of the posts. It was a shame for Johnson, whose goalkicking has improved enormously this year and had been exemplary until then, and prompted calls from the good crowd of, `who are ya?'.
The biggest roar of the night came when Dion Aiye scored 68 seconds after halftime. It wasn't really a concern for the Kiwis, who hadn't switched on after the break, but what was disconcerting was seeing Thomas Leuluai struggling to keep up as the Kumuls attacked his edge.
He had just come onto the field for his first taste of the World Cup after battling a groin injury. Coach Stephen Kearney had been keen to not only test the groin but also see how he went playing alongside Kieran Foran in the halves.
Leuluai's World Cup looks over now and the Kiwis' attempts to get approval to use a drug prohibited by the UK Anti-Doping agency seems academic.
It leaves the Kiwis short of backup should anything happen to Johnson, Foran or hooker Issac Luke.
Winger Manu Vatuvei was also replaced at halftime with what looked like a recurrence of an ankle injury and fullback Josh Hoffman was also struggling with a sore shoulder and Kearney will hope the pair are for next weekend's quarter-final. Foran also came off with 15 minutes remaining but it looked more precautionary.
Injuries were probably the biggest concern in a game like this. Set-pieces can be tidied up in training but the Kiwis can't afford to lose crucial players because the real business starts next weekend.
New Zealand 56 (Sonny Bill Williams 3, Roger Tuivasa-Sheck 2, Dean Whare 2, Bryson Goodwin, Frank-Paul Nu'uausala, Elijah Taylor tries; Shaun Johnson 8 gls) Papua New Guinea 10 (Dion Aiye, Wellingtoon Albert tries; Francis Paniu gl). HT: 40-0.
