The Federal Chamber of Automotive Industries (FCAI) said May new vehicle sales in Australia reached 92,561, a decrease of 8.1% year on year.
Year to date sales also slipped by 8.1% to 436,649 units.
Tony Weber, FCAI chief executive, said the May results followed the trend in the first quarter of the year in the automotive market.
"The Australian market has seen the same trend throughout 2019, resulting in an overall decrease of around 8% for the first five months of the year.
"We have attributed this trend to known market factors such as an economic downturn, drought, political events, the tightening of financial lending and lack of confidence in the market.
"Now that the federal election has been finalised, we are optimistic the market will improve over the next few months," Weber said.
Toyota was market leader in May with 18,820 sales, followed by Mazda with 8,578 sales, Hyundai which recorded 8,106 sales, Ford 5,788 and Kia 5,533.
The two top selling vehicles for the month were light commercial vehicles – the Toyota Hilux (4,206 sales) and the Ford Ranger (3,972 sales). In third place was the popular medium SUV, the Toyota RAV4 (2,917 sales) and in fourth place was the month's best-selling small car, the Hyundai i30 (2,901 sales).
SUVs continued their first place sales performance with 40,937 sales during May, passenger vehicles accounted for 28,890 sales, and LCVs 19,178.