MTA spokesman Ian Stronach said June was always a busy month.
Year-on-year figures show sales of new and used imported vehicles were higher than the same month last year.
The Suzuki Swift was the vehicle of preference for second-hand imported car buyers during June.
Nearly 400 Swifts were sold, figures show.
This was followed by Mazda's Demio (384) and the Nissan Tiida (367).
Mr Stronach said increases in both the used import and new car sales had been interesting.
"Local buyers are displaying a real appetite to upgrade and renew their vehicles - if that helps to modernise the fleet overall, then that has to be a good thing."
Motorcycle sales were also up with sales totalling 418 in June. This was up 42 per cent on the same month last year.