Dey (60), a Dunedin accountant, convincingly won the masters aged 60-64 title in a time of 1hr 55min 43sec for the standard 10km run, 40km cycle and 5km run course.
Dey took the lead near the end of the cycling stage and his superior fitness gave him a 4min 19sec win over Murray Vaile (North Shore), 2hr 02sec, and John Edwards (Palmerston North), 2hr 02min 45sec.
Dey was 41sec behind Lawrence O'Neill (Christchurch) when he completed the 10km run in 38min 59sec.
But he caught up on the cycling leg that he completed in 56min 22sec.
He was also fastest on the 5km run in 20min 22sec.
He first competed in national events in 1966 at the New Zealand junior athletics championships and he has three placings but the gold medal always eluded him.
But he wore a glow of satisfaction when he stood on the podium and the gold medal was placed around his neck at Auckland.
"It's a very special feeling," Dey said.
"I wanted it a long time ago but it's still special for a veteran like me. I'm very happy."
His best performance at a national championships came in 1971, when he won a silver medal in the senior men's 5000m at the New Zealand track and field championships at Inglewood.
His only other medals at national championships have come in the duathlon, where he has won a silver and a bronze medal.
Dey's best international performance was in Australia in 1969, when he won the silver medal at the transtasman university cross-country championships.
It was a clean sweep for Otago University students that day, with Alastair Hasell win-ning the gold medal and Chip Dunckley finishing third.
Dey has competed in the world masters duathlon championships twice.
He was 18th in Belgium in 2003 and 19th in Australia in 2005.
Last year he finished 46th in the world masters triathlon in Hamburg, Germany.
Dey has put a lot back into his sport through coaching and his athletes have won numerous New Zealand championship medals.
But the only gold medal was won by Sarah Bryant at the New Zealand secondary schools triathlon in 2001.
The best international performance by his athletes came in the world under-19 triathlon last year when Rebecca Grant finished fourth at Hamburg.
His other internationals have been Ian Edmond, who competed in the triathlon at the 1990 Commonwealth Games at Auckland, and Bruce Dellow at the world masters triathlon at Wellington.
It was also a good championship for Dey as a coach, with Anna Stott finishing third in the women's 20-24 grade in 2hr 02min 19sec and Amelia Kinnaird third in the secondary schoolgirls under-19 event in 44min 01sec.
Otago athletes won three gold medals and two bronze medals.
The other gold medals were won by Victoria Beck in the women's aged 25-29 grade in 1hr 43min 26sec.
Her split times were: 10km run (32min 52sec), 40km cycle (53min 09sec) and 5km run (17min 25sec.
Paul Gough won the Masters mens aged 40-44 gold medal in 1hr 44min 44sec.
His splits were: 10km run (34min 04sec), 40km cycle (50min 21sec) and 5km run (20min 19sec).
Dey, Beck, Gough and Stott have all qualified to compete at the world championships at Rimini, Italy, in September.
