Registrations of new passenger vehicles reached 6769 in July, the highest number since 1987. Registrations of commercial vehicles - at 2632 - were the highest since 1984.
Motor Industry Association said year-to-date commercial registrations are 25.5% ahead of this time last year while passenger vehicles are 5% ahead.
Chief executive David Crawford said Toyota remained market leader in July with more than 18% percent while Holden was second with 11.6% and Ford third with 11.2%.
However, Toyota's share slipped in the latest month - year-to-date, the Japanese company's market share is 19.6%.
Toyota's Corolla was the top selling car model in July, with 376 registrations, and Holden's Captiva was a distant second with 244 registrations.
Mr Crawford said the strong New Zealand dollar and low inflation means the real price of purchasing a new vehicle is better than it has ever been.