Australia's Qantas Airways said on Wednesday more than a million customers had their phone number, birth date or home address accessed in one of the country's biggest cyber breaches in years.

A cyber criminal has made contact with Australia's Qantas following a data breach last week that exposed personal information of six million customers, a company spokesperson told Reuters on Tuesday.

Qantas received an extortion attempt following the cyberattack and data breach at one of the Australian airline's call centers.