Dunning, who was contacted by police over the incident, said he had resolved the matter with the owner of the taxi, but on Tuesday the NSW Waratahs Rugby board decided the prop will face a committee hearing for bringing the game into disrepute.
"I had an accident on Saturday night with the hinge on a cab door," the 27-year-old said in the statement released by the NSW Rugby Union.
"I've had a chat with the owner of the cab and both me and the owner agree it's an accident and we've resolved it."
Dunning, who was part of the Wallabies front row decimated by England's scrum last November, was hopeful the matter would end there but the NSW Rugby board has been tough on any public incidents by its players and will take the matter further.
"We only became aware of this yesterday (Monday) so we are working quickly to gather the information from a variety of sources so that we can make an informed decision as soon as possible," said NSWRU chief executive Fraser Neill.
"Matt did the right thing by contacting team management and speaking to all the parties involved about the incident on Monday.
"But damage was caused to a car-door hinge and, as always, we must investigate the matter fully."