A backlog of orders as well as concerted marketing efforts by carmakers have minimized the impact from April's consumption tax hike on sales between April and June — but there are still concerns about sales volume after July, the chairman of the nation's automaker lobby said Tuesday.

"My biggest concerns are (the sales figures ) in July, August and September" after order backlogs run out, Fumihiko Ike, head of the Japan Automobile Manufacturers Association told a Tokyo news conference.

Ike, also chairman of Honda Motor Co., noted that domestic carmakers logged a 1.9 percent year-on-year drop in new four-wheel vehicle sales in the three-month period from April. On a monthly basis, new car sales in June recorded 0.4 percent increase from a year earlier, the first year-on-year growth in three months, he added.