He said for the Asean Car project to be materialised, Proton would need to get the agreement of all Asean countries.
The ministry, which oversees the automotive industry in the country, planned to discuss with Asean members about the project.
"It is a good concept but the detail needs to be worked out. It requires a lot of cooperation and meetings," he told reporters on the sidelines of the Khazanah Megatrends Forum 2017 here on Monday.
The Proton plant in Tanjung Malim. - Bernama
He said among the issues that needed to be ironed out with other Asean members included local content, vendors and component origin. Mustapa, however, is optimistic the project could take off in five years.
"Five years seems reasonable to kick start the project," he added.
In February 2015, Proton signed a memorandum of understanding with Indonesia's PT Adiputra Citra Lestari to further business opportunities between both companies in developing and manufacturing the Asean Car.
The project, however, stalled as Proton was undergoing a restructuring exercise and Mustapa said: "Proton wasn't ready at that time."
Yesterday, at an entrepreneurs and career carnival, Mustapa said newly appointed Proton chief executive officer Li Chunrong could help spur the national automaker's global foray.
