The defective airbags can shatter shards of metal upon activation if its propelling mechanism is exposed to high levels of moisture.

They have caused about 180 injuries and 18 deaths worldwide and been linked to at least one fatality in Australia.

The ACCC on Sunday published a revised recall list which added a further 1.1 million vehicles targeted for future airbag replacement, including the Mercedes Benz C Class, Ford Mondeo and Toyota Yaris.

An ACCC spokeswoman told AAP about 2.8 million vehicles were under "active recall" at the end of April, meaning consumers had been or were being contacted.

Of those, 1.9 million have already had their airbags replaced, leaving 900,000 yet to be completed.

The "future recall list" involves vehicles to undergo replacement some time from May 2018, which means there are about two million vehicles that haven't had airbags replaced in total.

Drivers of vehicles involved in the "future recall" group will be notified by email, phone or text message when it is time for their replacement to be completed, Assistant Minister to the Treasurer Michael Sukkar said.

"My message to all Australian drivers is do not ignore or delay responding to a letter from your vehicle manufacturer asking you to have airbags replaced," Mr Sukkar said in a statement to AAP.

"If you don't have your car's airbag replaced, you are taking a serious risk in terms of your safety."

He urged customers who have difficulties or delays to contact the ACCC.

The compulsory recall, which was announced by the government in February and already involved nearly four million vehicles, is one of the largest in Australian history.

The death of a 58-year-old man at Cabramatta, in Sydney's southwest, became the first incident linked to the faulty airbags in July 2017.

It came about three months after a 21-year-old Northern Territory woman was struck in the head by a small metal fragment when her airbag malfunctioned during a crash in Darwin.

Australian Associated Press