Alonso was left furious after he and his Mercedes rival came together at Les Combes on the opening lap of the Spa-Francorchamps race as they battled for second spot.
Hamilton had got a run on Alonso up the Kemmel Straight and moved to the outside in a bid to get a slingshot past him.
After getting ahead on the entry to the first right hander at Les Combes, Hamilton closed the door on Alonso, who had nowhere to go, and the pair came together – with the Mercedes being flicked up in to the air.
While Alonso was able to continue, Hamilton’s car had suffered damage and, as the result of a suspected water leak, he was advised to stop later around the lap.
Alonso was far from impressed with Hamilton’s driving, and hit out on team radio at the lack of awareness of the Briton when racing against other cars.
“What an idiot closing the door from the outside,” said Alonso. “We had a mega start but this guy only knows how to drive and start in first.”
While the FIA stewards did investigate the incident, they deemed that neither driver was to blame as it was put down to being a typical kind of crash that can happen on the opening lap as cars jostle for position.
A statement issued by the FIA said: “The Stewards reviewed the video evidence and determined that Alonso was on the inside at turn 5.
“Hamilton’s front wheels were ahead of Alonso’s at the entry to the corner. Alonso moved his car off line to the inside with both right side tyres fully on the kerb and even somewhat inside the kerb.
“At no point did Alonso appear to lose control or understeer. Hamilton turned into towards the apex of the corner with Alonso still alongside and the collision occurred.
“The Stewards considered that this was a first lap incident with a lot of movement relative to other cars in the first few corners, and thus take no further action.”
