A boy critically injured when his scooter was hit in a serious crash involving an alleged drunk driver has died after two weeks in hospital. 

The 12-year-old died on Sunday, 14 days after the September 3 accident on Queensland's Sunshine Coast when his scooter was hit by a Mazda utility.

The driver, a 27-year-old Bli Bli man, was initially charged with drink driving after returning a reading of 0.069.

Charges are expected to be upgraded before the driver faces court at Maroochydore on October 30.