Hong Kong-based carrier Cathay Pacific has revealed that a hacker gained access to part of its information system, compromising the personal data of as many as 9.4 million passengers.

The data included information such as passenger name, nationality, date of birth, home address, phone number, email address, passport number and identity card number.

Cathay Pacific has no evidence on whether the leaked data has been used for malicious activity.

The airline said that the breach did not affect its operations systems and that flights would remain safe.

Cathay Pacific CEO Rupert Hogg said: “We acted immediately to contain the event, commence a thorough investigation with the assistance of a leading cybersecurity firm and further strengthen our IT security measures.

“We are in the process of contacting affected passengers, using multiple communications channels and providing them with information on steps they can take to protect themselves.”

“We are in the process of contacting affected passengers, using multiple communications channels and providing them with information on steps they can take to protect themselves.

“We have no evidence that any personal data has been misused. No-one’s travel or loyalty profile was accessed in full, and no passwords were compromised.”

Cathay Pacific has informed the Hong Kong Police and is notifying the relevant authorities about the breach.

Hogg further added: “We want to reassure our passengers that we took and continue to take measures to enhance our IT security.

“The safety and security of our passengers remains our top priority.”

Cathay Pacific was established in 1946 and offers scheduled cargo and passenger services to more than 110 destinations worldwide.