NEW-CAR sales have slammed on the brakes and former favourite Holden has been hit the hardest, posting its worst monthly tally since 1948.

Official figures for the month of July show the new-car market slowed by almost eight per cent (from 92,754 in July last year to 85,551 last month) dragging the year-to-date tally into negative territory.

The Top Five brands were down by between 1.9 and 12.6 per cent but Holden fell by 39.3 per cent in July, in the wake of its factory closure last year.

Holden delivered just 3927 new vehicles in July, ranking ninth out of the Top 10 brands. This figure is less than Holden's previous low point of 4689 deliveries in March 2018, when it slipped to 10th.

Our changing taste in cars continues to favour utes - our top two sellers were the Toyota HiLux and Ford Ranger - and SUVs, while passenger cars such as the Toyota Corolla and Mazda3 dipped.

The sales slowdown means that most dealers are overstocked, which is likely to spark further discounts into August.

The big improvers in July were Kia, Nissan and Volkswagen. If Kia keeps tracking as it has done so far this year it will overtake Holden by the end of 2018, an unfathomable scenario a year ago.

Holden's market share - a key industry measure - has slipped from its previous low of 4.8 per cent in March to 4.6 per cent in July 2018.

Sales of the new imported Commodore are about one-third of the locally-made model's tally in the same month last year.

The grim figures have been released just days after Holden appointed a new boss, Dave Buttner, a 30-year veteran of Toyota.

When asked how long it will take for Holden to turn sales around, Mr Buttner told media earlier this week: "We have to be on the consideration set, increase awareness and work with our dealers to ensure the brand can get back to a level where it's profitable."

Top 10 cars July 2018

Toyota HiLux 3747 - up 0.1 per cent

Ford Ranger 2950 - down 4 per cent

Toyota Corolla 2594 - down 19.1 per cent

Mazda3 2443 - down 0.9 per cent

Mazda CX-5 2233 - down 3.1 per cent

Hyundai i30 2178 - up 2.6 per cent

Toyota RAV4 1853 - up 6.7 per cent

VW Golf 1628 - up 62 per cent

Nissan X-Trail 1603 - up 9.6 per cent

Hyundai Tucson 1490 - down 13.3 per cent

Top 10 brands July 2018

Toyota 16,915 - down 5.7 per cent

Mazda 8920 - down 6.4 per cent

Hyundai 7061 - down 5.9 per cent

Mitsubishi 5908 - down 1.9 per cent

Ford 5481 - down 12.6 per cent

Kia 4403 - up 3.2 per cent

Nissan 4260 - up 4.1 per cent

Volkswagen 3981 - up 4.1 per cent

Holden 3927 - down 39.3 per cent

Subaru 3366 - down 21.1 per cent

Source: Federal Chamber of Automotive Industries, sales in July 2018 versus July 2017.

This reporter is on Twitter: @JoshuaDowling