Sydney, July 2 -- Australian flag carrier Qantas said today that a significant amount of customer data has likely been compromised in a cyberattack.

The Qantas Group said in a statement that a cybercriminal on June 30 gained access to a third-party customer servicing platform used by a Qantas contact center.

It said that 6 million Qantas customers have service records on the compromised platform and it expects the proportion of data that has been stolen to be "significant."

An initial review confirmed that the data includes customers' names, email addresses, phone numbers and birth dates but not credit card details, passwords, financial information or passport details.

Qantas said the system had been contained and that its systems r...