Lexus' fourth generation RX luxury SUV has underlined its appeal in the marketplace by recording substantial sales growth on last year.

July 2016 sales of the RX were up nearly 40 per cent on the corresponding 2015 figure.

Lexus Australia chief executive Peter McGregor attributed the growth to the RX's striking design, high level of specification and newly introduced turbo model.

"The RX underwent a very significant change for the fourth generation model, delivering exceptional design including an award-winning interior, high levels of efficiency, driving performance and luxury features, all of which have found favour among our valued customers," Mr McGregor said.

"It has also grown in size with no impact on its sleek profile and dramatic styling, which has widened its appeal and added to its versatility."

The RX model line begins with the RX turbo, followed by the V6-powered RX 350 and hybrid-powered RX 450h.

Lexus' July result indicated positive growth for other model lines including the LX, sales of which were up more than 62 per cent on last year.

Total sales for the brand were also up six per cent year to date.