Sales of new autos slumped 7.5 percent in April from a year earlier to 319,482 units, with last month's auto tax hike on minivehicles acting as a brake on demand, industry bodies said Friday.

Sales of minicars, defined as having an engine displacement of 660 cc or less, plunged 22.5 percent to 121,111 units, marking the fourth straight monthly decline, according to the Japan Light Motor Vehicle and Motorcycle Association.

Minivehicles account for around 40 percent of new car sales in Japan, as demand has grown for less expensive cars with superior fuel efficiency.

Sales of cars other than minicars, meanwhile, rose 5 percent to 198,371 units, up for the first time in nine months, the Japan Automobile Dealers Association said, suggesting the negative impact of a consumption tax hike in April last year has petered out.

Demand for cars was sluggish during fiscal 2014, against a backdrop of the 3-percentage-point consumption tax increase to 8 percent — the first tax hike in 17 years.