The Masterton driver, with co-driving wife Sara, had the day before finished runner-up, by 15 seconds, to outgoing champion Dean Sumner, of Rotorua.
But a puncture in the last stage went against Sumner, and Emma Gilmour, from Dunedin – Mason's closest rival for the title – lost time changing a fuel pump, so Mason had a good chance.
He finished 90 seconds in front of local driver Stewart Taylor, not entered in national series. Gilmour came third overall.
"Finishing every day of the series this year was crucial," said Mason, who previously won the title in 2005 and 2006. "We had to keep an eye on Emma's times and stay out of trouble."
In the end he did it easily. Mason also won his home event, the Wairarapa Rally, earlier in the year. He also finished second at the Rally of Whangarei and the Rally of New Zealand held in the north Waikato and was fourth at the season opener at Otago.
