Google vowed to update its Pixel 4 smartphone line after it was discovered the smartphone can be unlocked by the faces of sleeping owners, TechRadar reported.

Device previewers reported on social media they could unlock the smartphone even when closing their eyes. Facial recognition is also used to activate Google Pay, app authentication and banking services.

A Google representative told TechRadar it is working on an option which requires open eyes to access the Pixel 4, which is due to be released in the coming months.

For now, Google recommends securing the smartphone with a pin, pattern or password.

In a statement, it told TechRadar the Pixel 4 face unlock “meets the security requirements as a strong biometric” for important activities such as accessing banking apps, adding “it is resilient against invalid unlock attempts via other means, like with masks”.

Google cut the fingerprint sensor featured in previous generations from its latest Pixel models, highlighting face unlock as a key way to access the device.

The Pixel 4 and Pixel 4 XL are due to go on sale on 24 October, priced $799 and $899 respectively.