The All Blacks sevens outclassed England 26-7 in the final to overtake South Africa at the top of the standings with two rounds to play in the nine-leg series.
They were never challenged on the final day, beating Wales 28-5 in the quarter-finals and Australia 19-7 in the semi-finals.
South Africa’s elimination by England in the quarter-finals means they trail New Zealand by seven points. Fiji are out of contention in third place ahead of the remaining tournaments in Glasgow and London in May.
Ben Lam and Tim Mikkelson scored first-half tries for New Zealand in the final before England’s Tom Powell reduced the score to 12-7 at half-time.
Tireless captain DJ Forbes crossed soon after the break before Sam Dickson made the result safe three minutes from the end, defying heavy rain which marred the second half.
Coach Gordon Tietjens says his team produced their best performance of the series, improving considerably on their fourth placing in Tokyo a week earlier.
“It’s a great, great victory in real challenging conditions,” he said.
“Our captain DJ Forbes was just, simply, simply outstanding … without singling out individuals, he was just quite amazing.”
England’s pace was earlier too much for South Africa and two-time Hong Kong defending champions Fiji in their semi-final.
However, they struggled for possession against a New Zealand side led up front by Forbes and 2013 world player of the year Tim Mikkelson.
“There’s a couple of us out there putting our heads in dark places,” Forbes said.
“There’s a place for that. We’re happy to do the contact stuff so maybe the conditions fell into our hands a little bit.”
New Zealand’s tournament win was their third of the series, following victories in Gold Coast and Wellington.
FINAL PLACING’S FOR THE HONG KONG SEVENS: 1. New Zealand, 2. England, 3. Fiji, 4. Australia, 5. South Africa, 6. Wales.
STANDINGS: New Zealand 136, South Africa 129, Fiji 112, England 104, Australia 87, Samoa 64, Canada 63, Argentina 61.