Owners of cars with faulty airbags must not drive them until the potentially lethal devices have been replaced, the consumer watchdog has warned.

The ACCC has stepped up its warnings on the Takata airbags, which have killed one Australian and 24 people worldwide, injuring another 266.

“The airbags degrade over time and can become lethal by misdeploying and firing metal shards at the car’s occupants,” ACCC deputy chair Delia Rickard said on Thursday.

“These airbags can kill and our advice is for consumers to check our website to see if their car is affected by this recall. If your car contains an alpha airbag, it should not be driven.”

The ACCC’s data, supplied by vehicle manufacturers, has found that 1.1 million of the “deadly’ Takata airbags have been urgently replaced in about 930,000 cars in the past year.

But 1.8 million remain on Australian roads following the compulsory recall announced earlier this year.

The most dangerous airbags under the recall – “alpha” airbags – were fitted to about 115,000 cars. Of these, 19,500 are potentially yet to be replaced.

The data identified all known registered vehicles and the number of affected airbag inflators that have not been replaced in each state.

The ACCC has warned consumers not to become complacent.

It said motorists should not drive cars containing potentially faulty “alpha” airbags until they have been fixed.

Ms Rickard said car owners should not ignore or delay responding to letters or calls from manufacturers advising the airbags needed replacing.

Consumers who are unsure whether their car is affected are advised to check their registration details on a new website. There is also a text service at 0427 AIRBAG.

This month marks the one-year anniversary since the ACCC’s Takata Taskforce began its safety investigation.

The global recall of Takata airbags is the largest in history and has affected millions of Australians.