It is understood that Proton has abandoned the normal usual pitch process and decided to select the two agencies following a credentials presentation, which involved eight to nine agencies.
The appointment was made earlier this year and the car maker is expected to make a final decision at the end of 2013.
Sources confirm that incumbent agency Leo Burnett and Proton parted ways at the end of last year.
It is believed that Naga DDB's prior link with Malaysia's other automaker Perodua, by holding the account for 16 years since the brand's launch, could be an advantage for the agency. Naga lost out on the contract in a pitch last year to Spin Communications and Lowe & Partners.