A man napping in his car at a Dunedin petrol station with an open bottle in his hand blew over the legal alcohol limit when roused, police say.

Sergeant Matt Lee, of Dunedin, said police were called to a Portsmouth Dr petrol station about 5.20am today after members of the public found a man asleep in his car.

Police were told the man was ‘‘sleeping with an open alcohol bottle in his hand’’, Sgt Lee said.

Officers found a 34-year-old man in the car.

His alcohol breath level was recorded as 338mcg — the legal limit is 250mcg.

The man was subject to an interlock licence and could only drive a car with an alcohol interlock device installed.

However, the vehicle he was found in had no interlock device, Sgt Lee said.

‘‘I think he’s just parked up over to the side [of the petrol station], so not at a pump.

‘‘Pulled up there to sleep, I think.’’

The car was impounded and the man was charged with driving contrary to an interlock licence.