Hann is recovering in hospital after breaking his collar bone and damaging his wrist in a motorbike accident in his home country. The world No 26 was due to play the winner of a second-round match on Thursday between the Irishman Michael Judge and Gerard Greene from Rainham in Kent.
But tournament organisers received notification from the player's mother last night that Hann would not be competing.
It is another blow for the Australian as he attempts to break into the world's top-16 elite for the first time. He had to scratch from last month's Grand Prix at Preston after his father suffered a suspected heart attack.
He delayed his return to Britain on compassionate grounds but now this latest mishap, believed to have occurred while Hann was on a scramble bike, will push him further down the provisional rankings.
The 23-year-old is expected to be out of action for at least six weeks.Reuse content