Hughes remains in a critical condition at St Vincent's hospital in Sydney after being struck in the head while batting for South Australia on Tuesday.
The incident - which occurred against New South Wales at the SCG - saw Hughes rushed to hospital after a sickening face-first fall onto the pitch that followed him being hit by a Sean Abbott bouncer.
The four-day fixture was abandoned on Tuesday due to the serious nature of the incident and the governing body confirmed on Wednesday that the round's other matches in progress - Victoria v Western Australia and Queensland v Tasmania - had also been called off.
A Cricket Australia statement read: "Cricket Australia (CA) today advises that the current round of Bupa Sheffield Shield has been abandoned.
"Following consultation with the players and the Australian Cricketers' Association (ACA), the Victoria v Western Australia match at the MCG and the Queensland v Tasmania match at Allan Border Field have been abandoned this morning.
"This follows yesterday's abandonment of the New South Wales v South Australia at the SCG match, in which South Australian batsman Phillip Hughes was seriously injured.
"Under CA's playing conditions, one point will be given to each team in an abandoned match."
Cricket Australia's executive general manager of team performance, Pat Howard, added: "We've spoken to players and the ACA, and given how players across the country are feeling right now, it's just not the day to be playing cricket and we understand that.
"We are continuing to offer all players and match officials counselling and support at this difficult time.
"Phillip Hughes continues to receive the best possible medical care.
"The thoughts of his team-mates and the wider cricket community are with Phillip and his family at this difficult time."
Further updating Hughes' condition, Cricket Australia team doctor Peter Brukner said: "He [Hughes] will have scans this [Wednesday] morning and a further update will be provided when the results of those scans are known."
Hughes seemed set to replace injured Australia captain Michael Clarke in the side's 12-man squad for the first Test against India, which starts next week.
He was on 63 not out when hit.
West Australian Shaun Marsh made 134 not out for the Warriors at the MCG on Tuesday and is now Clarke's likely replacement.