It's one of the last steps towards a mega-merger to create the world's fourth largest automaker.

The main shareholders in Peugeot owner PSA gave the green light on Monday (Jan 4) to the group's merger with Fiat Chrysler.

At a special shareholder meeting, the deal to form Stellantis, the new company, was backed by more than 99% of the votes cast by investors with double voting rights.

These include PSA's top stakeholder, the Peugeot family, as well as China's Dongfeng, and the French state, via Bpifrance.

A broader shareholder meeting was underway on Monday and FCA investors were also due to vote on the agreement.

PSA Chief Executive Carlos Tavares told the online meeting, that the final date for the closure of the deal would be announced shortly:

"Affordability, sustainability, and safety. We need to combine these three objectives. And in facing this challenge, we are coming to you with an answer, the merger between FCA and PSA, to create this new entity: Stellantis. Thanks to its scale effects, its capacities in research and development, innovation, and its ability to be present in every market in the world, it (Stellantis) will be able to face the challenge I had just described."

The shareholding structure will be altered as part of the merger.

And existing double voting rights - which are accrued over time and give investors more weight in decisions - will not be carried over.

Tavares will take the helm of the merged group.

He's under pressure to revive the carmaker's fortunes in China and rationalise a sprawling empire.

Like the car makers rivals, there will also be a focus on creating cleaner cars.

Stellantis will have 14 brands, from FCA's Fiat, including Maserati and U.S.-focused Jeep.