Australian team doctor Peter Brukner announced yesterday afternoon Hughes had died, surrounded by family and close friends.
He said Hughes never regained consciousness after his injury, but was not in pain before he died.
The news prompted messages of support from around the world. Play was suspended for the day in the third test between New Zealand and Pakistan in Sharjah, United Arab Emirates.
Moises Henriques is comforted by Simon Katich at St Vincent's Hospital. Photo / Getty Images
Australian cricket captain Michael Clarke, who Dr Brukner described as being like an older brother to Hughes, read a brief statement on behalf of Hughes' parents, brother and sister.
"We're devastated by the loss of our much-loved son and brother Phillip. Cricket was Phillip's life, and we as a family shared that love of the game with him ... We love you," Clarke said.
The left-hander, who would have been 26 on Sunday, was at the crease for South Australia when he attempted to hook a short-pitched ball from New South Wales fast bowler Sean Abbott.
Although he was wearing a helmet, the ball struck an unprotected area at the back of his head. He stumbled, leaned over and then collapsed.
Many former and current Australian players visited Hughes in hospital, including Abbott. The 22-year-old, who looked pale and exhausted when he left St Vincent's following Hughes death, has been offered support and counselling.
Dr Tony Grabs, a surgeon and director of trauma services at St Vincent's, said Hughes died from a rare injury - there have been only 100 documented cases of vertebral artery dissection, which results in severe bleeding on the brain.
Cricketer Dave Warner and his partner Candice Falzon and and Matthew Wade and his partner leave St Vincent's Hospital. Photo / Getty Images
Australian Prime Minister Tony Abbott described Hughes as a "young man living out his dream".
"For a young life to be cut short playing our national game seems a shocking aberration," he said.
International Cricket Council chief executive David Richardson said Hughes' death was devastating for the cricketing community.
In Sharjah, Hughes' photo adorned the scoreboard and there was disbelief that a test cricketer could lose his life in such a fashion.
The rawness and numbness of the news meant treating the day as a rest day was the only appropriate course of action.
Black Caps coach Mike Hesson said the team was devastated.
"It's an unthinkable loss and I can tell you it's an incredibly sombre dressing room."
New Zealand players expressed their condolences on Twitter.
New Zealand Cricket chief executive David White said: "Cricket is a family. Quite apart from its super-competitive edge, it is a game of kinship, mateship and friendship; of camaraderie and community."
Hughes is the second player in recent years to sustain a fatal blow. South African Darryn Randall, 32, died last year after being struck during a Border Cricket Board Premier League match.
Phillip Joel Hughes
Photo / AP
• Born Macksville, NSW.
• Played 26 test matches for Australia scoring 1535 runs, including three tons, after making his debut in 2009 against South Africa
• In his second test match in Durban, he became the youngest cricketer to score two centuries in a test.
• Played 25 ODIs for Australia scoring 826 runs, and more than 114 first-class matches in a career starting in 2007.
