With two-in-seven cars on the road affected, the RACQ's head of technical and safety policy Steve Spalding said cars manufactured before 2012 were the biggest safety risk.'The risk factors seems to increase anytime from six or so years onwards,' he told Daily Mail Australia on Thursday.
'It's absolutely important motorists take this issue seriously and don't just ignore the advice.
But some 500,000 cars thought to have the faulty safety device remain unaccounted for as Holden and Tesla refused to reveal how many of its vehicles are affected models, News Corp reported.
An earlier voluntary recall process was deemed ineffective.
There are four million cars in Australia which have the defective airbag.
It is understood most of the new vehicles added to the recall list had faulty airbags made by Takata in Germany - adding to the list of cars which had devices made in Thailand, Mexico and Japan.
One million vehicles yet to have their airbags replaced following a voluntary recall last year and the 1.3 million added to the government list this week.
More than 25,000 cars on the road have the alpha airbag fitted which the government said 'pose an immediate and critical safety risk'.