A 57-year-old school-bus driver was arrested for dangerous driving causing grievous bodily harm after his vehicle hit a woman and her grandson in Happy Valley on Hong Kong Island on Monday.

At around 7:15am, the minibus traveling uphill along Tai Hang Road hit the 63-year-old woman and her eight-year-old grandson, who were crossing the road outside Grand Deco Tower, Oriental Daily reported.

The woman protected her grandson from being hit directly by the vehicle. She was seriously injured on her head and legs and ended up lying unconscious on the road.

She was sent to Queen Mary Hospital, where she was admitted to the intensive care unit in serious condition.

The grandson was not seriously injured but was sent to Ruttonjee Hospital in Wan Chai for treatment.

The driver was given a breathalyzer test at the scene and the reading showed that he had consumed alcohol but not above the legal limit.

Police are also investigating whether the woman and her grandson were jaywalking, as there was a crossing facility 100 meters away from where the accident happened, Wen Wei Pao reported.