"In Christchurch and in Auckland in particular, when your builders, your plumbers, your bricklayers, your electricians etc are doing well, they will buy their utes and their vans for their trade."
The top three best-selling models for April were all light commercial vehicles - the Ford Ranger, Toyota Hilux and Nissan Navara.
More utes are also now being sold as dual purpose commercial and family vehicles as the fitouts become more "carlike", Crawford said.
"They are being used for a mixture of commercial during the day and family during the nights and weekends."
A stronger New Zealand dollar, particularly against the aussie, euro and yen, is helping lower the cost of new vehicles in local currency terms, Crawford said.
Prices are also weakening ahead of the release of new models.
Increased sales and promotional activity during April and May before the June agricultural fieldays is also stoking sales of commercial vehicles to the agricultural and rural market.
Still, Crawford said sales to the agricultural sector may weaken later in the year after Fonterra lowered its payout to dairy farmers to reflect declining global prices.
Meanwhile, sales of new passenger vehicles in April rose 3.6 per cent to a 26-year high for the month of 6375. The Toyota Corolla was the top selling passenger vehicle for the month. Sales in the first four months of the year are 5.2 per cent ahead of the year earlier period.
In the first four months of this year, total new passenger and commercial vehicle sales are 7 per cent ahead of last year at 42,545.
New vehicle sales hit a record 127,179 last year, beating the previous record of 123,247 from 1984, and ahead of the 113,294 recorded for 2013.