IT officials on Wednesday apologised after an update to the LeaveHomeSafe app the day before led to the vaccine pass QR code of some Google and Huawei phone users being deleted.

The Office of the Government Chief Information Officer (OGCIO) blamed the service provider for the "technical error," adding that an updated version had been released on the same night to rectify the problem.

Officials said if Google and Huawei phone users had updated the app to version 3.2.4, either manually or automatically, their vaccine records or exemption codes stored in the app would have been deleted.

They appealed to the public to check the vaccine pass stored in their mobile app and update the app to the 3.2.5 version if the record had disappeared.

"The OGCIO apologised to the public for the inconvenience caused. A warning letter had been issued to the service contractor requesting its serious follow-up action and measures to improve the control procedures," said a spokesman.

He added that the office will also strengthen the testing and supervision of LeaveHomeSafe updates to ensure the mobile app's smooth operation.