Investing.com-- Qantas Airways (ASX: QAN ) shares fell on Wednesday after the airline confirmed a cyber incident at a third-party contact centre exposed customer data, including names, email addresses, and frequent flyer numbers.

The stock dropped as much as 4.1% to A$10.32 as of 02:02 GMT, underperforming the broader market.

Qantas said the breach on Monday affected a platform holding records for 6 million customers, though financial data and passport details were not compromised.

"We are continuing to investigate the proportion of the data that has been stolen, though we expect it will be significant," the company said in a statement.

The airline has contained the system and notified authorities, including the Australian Cyber Security Centre and federal police, it said.

The incident has raised fresh concerns about data security at Australia’s flagship carrier, which has faced reputational challenges in recent years.