David Crawford, head of the MIA, said July was "an exceptional month" for new vehicle sales.
"With a strong New Zealand dollar and low inflation the real price of purchasing a new vehicle is better now that it has ever been," he said.
"I think consumers have held onto their cars for a while and now taken a chance to replace the big ticket items."
Crawford said double-cab utes and SUVs were selling particularly well in the commercial segment. He attributed that to momentum in the Christchurch rebuild and the Auckland housing market.
The best-selling commercial models over the past 12 months have been the Toyota Hilux and Ford Ranger, taking 17 per cent and 15 per cent market shares, respectively.
The SUV segment was the most popular last month, taking a 27 per cent share of total registrations.
As reported in the Herald last month, business in the luxury car trade has been booming this year.
Audi New Zealand, a division of Audi in Germany, sold 967 vehicles in the six months to the end of June.
Crawford said movement in that sector was usually a lead indicator to economic recovery.
He said the reason new vehicle sales were so strong in the 1980s was because those were the days before used vehicle imports were allowed. "We only had new cars back then."
Overall, the most popular car maker in New Zealand last month was Toyota, with an 18.1 per cent market share (1,159 passenger cars and 544 commercials). Holden was second with an 11.6 per cent share of the market.
Toyota is also leading in the year to date, followed by Ford and Holden.
The top-selling car model last month was the Toyota Corolla with 376 registrations, ahead of the Holden Captiva with 244 registrations and the Suzuki Swift with 239 registrations.