Toyota's Australian engineers have subjected the upcoming LandCruiser 70 Series upgrade to more than 100,000km of testing in some of the harshest conditions around the country.

Around 70 per cent of the testing was conducted in off-road conditions, including everything from corrugated dirt roads to rugged cattle properties with severe washouts.

Local testing and evaluation, which focused on the best-selling single cab-chassis, has confirmed the new vehicle will be even stronger due to the adoption of a stiffer new frame with thicker side rails, reducing vibration and improving handling and stability.

The Australian engineers have tuned new safety features including vehicle stability and traction control for optimum performance in areas where the vehicle is mostly used - dirt roads, rural properties and country highways.

All 70 Series variants - single and double cab-chassis, wagon and troop carrier - will be equipped with these safety features as well as hill-start assist control, brake assist, electronic brake-force distribution and cruise control.

The single cab is expected to attract the maximum five-star safety rating with five airbags, gaining curtain-shield airbags and a driver's knee airbag in addition to the existing driver and front-passenger airbags.

Toyota Australia's executive director sales and marketing Tony Cramb said the updates, due to arrive in the last quarter of 2016, have been made possible by a substantial commitment of engineering resources and investment by the company in Japan and in Australia.

"The upgraded 70 Series LandCruiser range builds on this iconic vehicle's fit-for-purpose appeal with improvements that reinforce its heavy-duty abilities, durability and unapologetically rugged character," Mr Cramb said. "At the same time, it receives important safety and emissions updates that are required by many customers - as well as regulators - to enable Toyota to continue selling the 70 Series in the Australian market," he said.

The new range retains the 4.5-litre V8 turbo-diesel engine with common-rail direct injection and an intercooler, which will be certified to the Euro 5 emissions standard.

It will also be fitted with piezo injectors for even better response at low engine speeds. The manual-only transmission is retained with revised gearing aimed at improving fuel economy and lowering noise, vibration and harshness.

Local engineers, who retuned the suspension by adjusting spring and damper rates to match the stiffer new frame, also confirmed the suitability of the set-up for Australian conditions.