Starc finishes things off with a short ball, as Trent Boult hooks to Behrendorff at fine leg.
Starc becomes the first man to take three five-wicket hauls in World Cup history.
In the end, a comprehensive victory for Australia and that cements their place alongside India as the heavy favourites at this World Cup.
Who saw that coming six months ago?
Starc finishes with 5-26, stunning figures as New Zealand are rolled for 157 in response to Australia's target of 244.
Australia continue to have just the one stumble at this tournament, the early defeat to India, but since then they've grown and improved and heading to the pointy end of the tournament they have as much momentum as anyone.
Today it was Usman Khawaja (88) and Alex Carey (71) who helped them scrape to a competitive total.
And it looks as though they've found their bowling lineup to take through to the knockout games – Starc, Cummins (1-14) and Behrendorff (2-31) started things off, while Nathan Lyon has also found a home as the team's frontline spinner.
Steve Smith (1-6) even chipped in as New Zealand slumped to a disappointing defeat.
Elsewhere overnight, Pakistan scraped home against the winless Afghanistan to apply the blowtorch to England.
England plays India tomorrow night in a match they need to win to keep their destiny in their own hands.