Green (20), a student at the University of Otago, propelled his implement like a missile in a remarkable display of javelin throwing in difficult wind conditions.
He won the senior men's event with a throw of 51.41m from training partner Cameron O'Neill (Taieri) 47.98m.
Both throwers are trained by Raylene Bates, who was the athletics section manager of the New Zealand team at the Beijing Olympics.
Green, who comes from Christchurch, won a silver medal in the junior men's javelin at last year's New Zealand championships at Auckland.
He has a best throw of 56m and is aiming to crack the 60m barrier this season.
His efforts into the ferocious wind indicate that he should reach his target distance this summer.
His three legal throws were 48.59m, 46.98m and he left his best for last with 51.41m.
O'Neill (18), a sports studies student at the Otago Polytechnic, was fourth in the New Zealand junior championships last year.
He is looking for a medal this season.
His best throw was his first and he followed it with 47.58m, 44.09m, 47.54m and 46.53m with his four other legal throws.
The top women's javelin performance was thrown by Hill City's Maddy McKinlay (15) with 30.34m.
She was part of the Otago Girls High School junior girls' team that won the women's 4 x 100m relay in 53.47sec.
The other team members were Monika Qauqau, Ella Johnston and Annabelle Harray.
The Otago Girls senior girls' team was second in 54.42sec.
It was the team that will be defending the New Zealand secondary schools junior girls' relay title at Hamilton next month. Leslie Taylor (Taieri) was another athlete who overcame the difficult wind conditions to win the junior men's 400m hurdles in 65.12sec.
Taylor (17) won a bronze medal in the 300m hurdles at the New Zealand championships last March.
He is aiming for a medal in the same event at the national secondary schools championships at Hamilton next month.
He will also be contesting the 400 flat race.
Leith's Kirsty Morris (23) was blown off the track by a strong gust of wind during the mixed men's and women's 3000m.
She won the women's section in 10min 40.90sec.
"I was worried that I might be disqualified for going off the track," Morris said.
"The wind was insanely strong."
Morris, who completed her Masters degree in Town Planning last week, had never been blown off the track before.
Morris was also troubled by the wind when she won the women's 800m in 2min 32.67sec.
Her light frame was pushed back by the strong wind in the back straight.
"It was like hitting a brick wall," she said.
"It was just so hard to push against."
The wind also affected Tony Payne (Caversham) when he attempted to break away from the field after four laps in the men's 3000m.
He gained a 20m advantage with the wind behind him but the pack caught him when the wind stopped him in the back straight.
In the final lap it was the stronger and more experienced John Winsbury (Leith) who was able to break away in the back straight and win by 4sec from James List (Ariki) in 9min 19.02sec.
