The companies said their joint intention was to explore several new projects covering shared products, technologies and manufacturing capacity among the automakers.
"As a consequence, it has been agreed that the strategic cooperation between Nissan and Mitsubishi Motors could be expanded across the broader Renault-Nissan Alliance," Renault-Nissan Alliance said in a statement.
Between Nissan and Mitsubishi Motors, it is expected that the existing NMKV joint-venture company will be extended to co-develop a new small-segment car including a specific electric version that can be sold on a global basis, it added.
"The basis for this product will be from a jointly developed 'Kei car' platform of the type popular in the Japanese domestic market. Further details of all products, markets and manufacturing will be announced separately," it said.
Nissan and Mitsubishi Motors have an existing joint venture company called NMKV which was established in June 2011 for co-developing a range of Kei cars for both brands. The first of these products - the Nissan Dayz and Mitsubishi eK wagon - went on sale in Japan this year. Both products are manufactured at the Mitsubishi Mizushima plant in Japan.
Commenting on the development, Renault-Nissan Alliance President and CEO Carlos Ghosn said: "Nissan and Mitsubishi Motors have jointly benefited from several collaborations in the past, most recently the successful joint-venture on Kei cars in Japan.
"I welcome the direction being taken towards this broader cooperation, creating new opportunities for Renault in addition to further leveraging the productive relationship between Nissan and Mitsubishi Motors."
The Renault-Nissan Alliance and Mitsubishi also confirmed their intention to share technologies and product assets related to electric vehicles and latest-generation platforms. "Based on the current direction of discussions between Renault and Mitsubishi Motors, it is firstly expected that two new sedan models would be launched under the Mitsubishi brand, based on vehicles from the Renault portfolio," the statement said.
Secondary and additional studies around other projects will then be considered, it added.
The first sedan, to compete in the full-size D-segment markets of the US and Canada, would be manufactured at the Renault-Samsung plant in Busan, South Korea.
The second sedan model would compete in the global C-segment. The manufacturing location for this product is under discussion, it said.
"The new opportunities could be described as evidence that the ongoing collaborative projects between Mitsubishi Motors and Nissan have brought positive results, and Mitsubishi Motors hopes that any new collaborative projects with the Renault-Nissan Alliance would bring us further merits, Mitsubishi Motors Corporation President Osamu Masuko said.