An alleged drunk driver will face court after a morning breath test gave a blood alcohol reading that was too high for a breathalyser to calculate.

Police say a 51-year-old Kelmscott man stopped at 10.50am while driving on Royden Road in Roleystone on March 13 was barely conscious.

Camera Icon The driver’s blood alcohol was allegedly calculated to be 0.307 - six time the legal limit. Credit: WA Police

A bottle of alcohol was found on the front seat passenger seat while empty bottles were found on the floor of the car.

A WA Police spokesperson said a roadside blood alcohol test allegedly produced a reading that was too high for the machine but was later calculated to be 0.307 - six times the legal limit.

Camera Icon Police say these alcohol bottles were found in the car. Credit: WA Police

The driver was charged with driving under the influence of alcohol and will appear in Armadale Magistrate’s Court on June 25.