The next-generation Mercedes-Benz G-Class has been spied undergoing hot weather testing in southern Europe.

mercedes-benz-g-class-spy-2-hero

Stylistically, the new off-roader will be boxy, angular and completely unrepentant about it. A first glance, the new car doesn't look that different to the today's car, but it's clear that the next-gen model will be significantly wider.

Under the skin, reports indicate that the next G-Class will be largely new, but may continue to use some structural elements from the current car, which can trace its lineage back to the original 1979 G-Wagen.

mercedes-benz-g-class-spy-6-side

Thanks to the use of lightweight materials, including high-strength steel and aluminium, the next-generation G-Class will shed between 200 and 400 kilograms of weight.

Under the bonnet, the G-Class will use the latest Mercedes-Benz engines, including a turbo-diesel V6. Petrol and AMG variants will likely employ a version of the company's 4.0-litre twin-turbo V8 that's used in the C63 and GT.

The interior is said to be completely revamped, with many elements borrowed from the new E-Class. This will likely include a modern instrument pack and a high-end infotainment system.

mercedes-benz-g-class-spy-8-rear

Rumour has it that the new G-Class will make its global debut late in 2017, meaning that it won't arrive in Australian showrooms until some time in 2018.

That said, a product roadmap included in the last week's mid-year sales presentation made no mention of the G-Class, although it does list the Nissan Navara-based ute, an S-Class facelift, and an E-Class coupe amongst its 2017 models.

Regardless of its exact reveal date, the new G-Class will be produced again by Magna Steyr in Austria.