The new vehicle market was now performing at a level similar to before the global financial crisis, said MIA chief executive David Crawford.
"The numbers do show new vehicle sales are back to pre-2008 levels. Some people just seem to have a little bit more confidence around their businesses."
Commercial vehicle sales were "particularly pleasing", he said. Last month was only the fourth time since 1981 that sales in this segment exceeded 2,000 units (previous times were 1982, 1984 and 2008).
Crawford said the commercial vehicle sales growth was partly because rental car agencies were refreshing their fleets at the start of the year, and because of momentum in the Christchurch economy.
Another reason was possibly because more families were buying four-wheeled-drive utes instead of sport utility vehicle (SUVs), which was traditionally the most popular segment.
With the end of the financial year approaching, some businesses were also likely to be spending up, he said.
Toyota took out the largest share of total registrations (18.4 per cent), coming ahead of Ford and Nissan.
New Zealand's most popular passenger car model last month was the Toyota Corolla with 366 registrations, ahead of the Suzuki Swift with 263 and the Volkswagen Golf with 144.
The Toyota Hilux took out the commercial market, top-selling with 338 registrations.
The SUV segment dominates, with 25.5 per cent of total registrations, followed by the small car segment with 18.5 per cent.